Next week, we will receive a Banned/Restricted list update. This is at the forefront of everyone's mind due to the overwhelming and continual dominance of the Caw-Blade archetype in Standard, but the DCI may take action in other formats as well.
Caw-Blade is so overpowering that it doesn't have a bad matchup. When Jund was the best deck in standard (a title which was lost when Rise of the Eldrazi was released), it at least had an awful matchup against monored decks. When Faeries was the best deck in standard, US Nationals had a top 8 with 32 copies of Great Sable Stag and 31 copies of Volcanic Fallout. It was possible to hate out both of those decks. Caw-Blade? Not so much. Unlike Faeries, Caw has the tools to deal with anything people throw at it. Vengevine? Meet Condemn or Oust. Torpor Orb? Meet Spell Pierce and Divine Offering. The deck simply is capable of being built to handle any threat that is posed to it, and the only reason people are having even slight success with decks like Elves or Vampires is that the Caw-Blade players are warping their deck to fight the mirror so much that they're not even playing sweepers or Gideon Jura.
Furthermore, the Open Vampires won in Indianapolis was one which every SCG player over 15 points was playing in the Invitational. The following Open, also won by Vampires, coincided with Pro Tour: Nagoya, which several SCG series regulars were attending. What did the Invitational Standard format look like? Caw-Blade everywhere.
Despite the claims of those who say this format is amazing because the more skilled player wins the mirror the vast majority of the time, deckbuilding and metagaming should count for something. Tournaments should be something more than a test of the same mirror match every round.
Jace, the Mind Sculptor
Banning Jace, the Mind Sculptor isn't really a solution to the Caw-Blade problem. It was a popular subject of discussion after 4 Caw-Blade and 4 RUG decks made top 8 of pre-NPH Grand Prix: Dallas, but Jace isn't the key to Caw-Blade. It's obviously a good card - probably too good at that - but it's a card which can and has been fought successfully in the past. If Jace were an $8 card instead of an $80 card, I doubt the calls for its banning would have ever reached the level they peaked at. It was an issue that every deck that was doing well was a Jace deck, but at least there were multiples, and decks like monored remained viable to punish the other players for taking too long.
So what are the fringe decks with any success since NPH came out? Twin, RUG, Bluemanji, Boros, Vampires, and Elves. The first 3 are Jace decks. What happens if Jace and only Jace gets banned? They probably disappear entirely. What happens to Caw-Blade? People either stick to blue for the countermagic or switch to red and play Boros so they can continue to lay down turn 2 Mystic into turn 3 Batterskull, or stick Swords on Squadron Hawk.
With all that said, if Wizards decides to ban something, Jace is quite likely to be on the chopping block.
Banning Stoneforge Mystic yanks the ridiculous engine out from under Caw-Blade, turning it back into Kibler's Caw-Go deck. It loses the ability to drop Batterskull and simply lifelink its way past any aggro deck, but can still put up a lifegain plan if deck builders decide to run the equipment the hard way. The free wins go away, but the deck remains. This is the ideal ban, and would be a blatantly obvious decision.
Except for one thing.
Stoneforge Mystic is in an event deck. A deck which people are supposed to be able to open up and play in FNM. This is a problem. There's precedent - Skullclamp was banned even though it was in a precon. Unfortunately, that was under a different marketing system. The only saving grace here is that it is now possible for FNM to be made Extended, and WotC could do a last-minute marketing push to get the stores to label the Stoneforge deck as an "Extended Event Deck" or some such. This is still a poor situation, since the deck doesn't have any cards from the larger format, but this would still be a terrible position to put new players in.
This is the best single card by far to ban to fix the format, but it would be an incredibly hard decision for Wizards to make.
So why not skip Mystic and ban Batterskull instead? This leaves the deck intact, but takes away the free wins.
Let's look at history. Caw-Blade was the best deck before Batterskull got printed. It'll probably continue to be the best deck. Let's turn to ancient history. Specifically, the last time cards got banned in Standard.
Going in to our meetings that would ultimately lead to this eight-card ban, we knew the goal was to make a statement. We had to alter the reality of the format, but we also had to let the world know without a doubt that we “slew the dragon” as it were.
Taking away Batterskull doesn't do this. What would the reaction of the player base be if they ban a card because Caw-Blade is the best deck... and then Caw-Blade wins the next major event? Wizards looks dumb, Jace is still too expensive for a large number of players to afford, and nothing's really changed. Sure, monored gets better, but does this really change all that much? Caw-Blade goes back to playing Mortarpod, Sword of War and Peace still lets them lifelink away, and it is still in all likelihood the best deck in the format.
Batterskull could be banned, but if it's the only card banned, it won't change very much.
Jace and Stoneforge Mystic
Ding dong, the witch is dead. Banning both Jace, the Mind Sculptor and Stoneforge Mystic leaves no doubt that Caw-Blade is eliminated as a deck, and people won't simply swap the blue half of the deck (as little as 8-10 cards in some cases) for another color.
Some people have postulated that in a world without Caw-Blade, Splinter Twin or Valakut, the Molten Pinnacle becomes dominant. I don't believe that. It might have been true that Valakut would have locked out certain "not fast enough" aggro decks before New Phyrexia thanks to Overgrown Battlement, Slagstorm and Pyroclasm, but now, there's plenty of power to go around. Every color has access to Dismember to solve the Splinter Twin problem, and the aggro players can reload with Shrine of Burning Rage, get out of red sweeper range with Tempered Steel, or play a tempo game and counter sweepers with Spell Pierce and Unified Will or Corrupted Resolve.
It's true that a lot of people would just fall back to Valakut or Twin early on, since they're at least obviously good enough; but the demise of Caw-Blade gives us breathing room to build decks with a different core.
This, of course, also requires Wizards to figure out a way to explain to the new players why they can't play with the event deck they just bought.
Jace and Batterskull
The worst of Mystic's abuse gets axed from the format here, and with Jace gone there's no real incentive to play the rest of the Caw-Blade shell. Boros and Green-White Vengevine decks will pick up where Caw-Blade left off, but they'll at least have to pay equip costs and risk losing tempo to removal spells.
This plan probably has the largest intersection of how good it would be for the health of the format combined with how likely Wizards is to do it.
Nuke it from Orbit
The only way to be sure, a full format reset would axe Jace, the Mind Sculptor, Stoneforge Mystic, Valakut, the Molten Pinnacle, Splinter Twin (or Deceiver Exarch), and just knock out all the top decks in a single swing; basically putting everyone back at square one. This seems extremely unlikely - I can't see Wizards deciding to ban Twin or Valakut without those decks actually doing anything to the format yet - but would prevent the format from stabilizing with one of the current second-tier decks at the top.
Nothing's currently banned in Extended. When the format rotates prior to the presumed Spring PTQ season, it will lose Lorwyn block (good riddance, Faeries), and pick up Innistrad. With Stoneforge Mystic rotating out of Standard, I can't see Wizards pre-emptively banning it in Extended, and there are no other cards I'd seriously consider getting a ban there. The upside is people who are angry about their Caw-Blade deck getting banned have what's likely to be a tier 1 deck ready for Extended anyway. Some discussion I've had with Corbin Hosler on twitter has led us to conclude that Bant-Blade with Sovereigns of Lost Alara and Eldrazi Conscription is the obvious deck going into the new format.
Modern was a big hit at the community cup, so it's possible Wizards will announce Modern as a real format. If so, Hypergenesis may get added to the ban list.
Mental Misstep shook this format up a great deal. It's likely that Wizards doesn't want to tweak Legacy right now, but if it continues to stabilize around the same few blue decks, there are a few ways available to shake up the format.
First off, let's talk about the 51 new Commander cards.
Flusterstorm, Homeward Path, and Scavenging Ooze have some degree of Legacy application. Flusterstorm is a Spell Pierce that's better in a counter war and a Storm hate card that's not dead elsewhere. The drawback is it can't counter Jace. This is potentially the card that would see the most play.
Homeward Path is a niche land, but it's extremely potent in its niche, neutering theft effects like Sower of Temptation and Vedalken Shackles. It's an immediate 1-of in Knight of the Reliquary decks. Mind Harness and Threads of Disloyalty suffer greatly from this printing.
None of these has a very strong overall effect on Legacy, and none of them will drastically alter the format. So, what would it take to pull Legacy out of its current Blue Period?
Ban Mental Misstep
This would immediately re-diversify the format to where it was before. Still, we've never seen Wizards ban a counterspell for being too good, and it's possible Wizards considers Misstep's impact on Legacy a good thing. Among other reasons, it removes all possible need for them to ban the extremely expensive Candelabra of Tawnos.
Still, this isn't happening for at least a year, and the format would have to get in pretty dire straits for this to happen even then. Misstep is in some ways a self-regulating card, but since Spell Snare also exists, people can't reasonably be expected to build decks that dodge them entirely.
(As an aside: a Force of Will ban is almost certainly out of the question - FoW is regarded as an "escape valve" for when things would otherwise be far too broken.)
We're talking about Legacy here. This combo is exactly 2 mana cheaper than the Standard infinite combo, doesn't have the luxury of Flashing out its first piece on its opponent's endstep, and exists in a world with Force of Will.
Why is this banned?
It could fit into Enchantress decks, allowing people to tap Argothian Enchantress to untap a land which has multiple Wild Growths and Utopia Sprawls attached, but that's not a big deal- they're already drawing most of their deck, laying Serra's Sanctum or Carpet of Flowers, and casting Emrakul, the Aeons Torn on the same turn Earthcraft would let them anyway.
Taking Earthcraft off the banned list would be doing us all a favor by making the list shorter, but wouldn't change the format very much at all. This seems like it should be a real possibility.
Unban Land Tax
Land Tax isn't broken, and is a solid way to encourage people to play larger numbers of basic lands. The downside is it slows games down further, drags things out further with Sensei's Divining Top, and fuels what was once considered a degenerate card-drawing engine with Scroll Rack.
Now, let's all go look at the effect of Land Tax and Scroll Rack. You search your library for 3 lands. You then Rack away 2 of them, spending 1 mana, and draw 2 fresh cards. There are now 2 lands on top of your library. (If you have extra lands, you rack away all but 1 so you can make your drop for the turn, unless you have enough. Then you rack away all of them.)
Either way, Land Tax is either the most powerful long-term card advantage engine in Legacy, or not good enough to play at all. That's exactly the sort of thing which isn't going to get unbanned.
Unban Mystical Tutor
With Mental Misstep's existence, does Mystical Tutor really need to stay on the banned list? Control players can simply employ the "counter the tutor" technique of old, while combo players regain some consistency. I can't see Wizards unbanning Mystical so soon, but it's worth keeping in mind for the future.
Unban Worldgorger Dragon
The classic 2-card combo is Worldgorger Dragon plus Animate Dead, with Necromancy as a backup. Then, while your permanents are blinking in and out of play, you tap your lands until you've got millions of mana and then decide that the Animate Dead is going to bring back Shivan Hellkite instead.
So, why's this on the banned list at all? Well, for starters, if there's nothing else in the graveyard and no way to ever get a non-Dragon creature in the graveyard, then the game ends up in an unbreakable infinite loop, which forces a draw. Dragon matches often go to 4 or 5 games because the Dragon player will force a draw instead of a loss, and that's not something Wizards wants to see people doing. Cards like Char and Earthquake do it from time to time, but not with the maddening frequency of the Dragon deck. This is going to stay on the banned list even though it's an inferior strategy for the same reasons as Shahrazad.
It's fairly likely that something will get banned in Standard. Stoneforge Mystic is the best option by far, but due to outside circumstances it's not likely. If Wizards actually does ban Mystic, they deserve a round of praise for being willing to make the hard decision. Banning Batterskull plus Jace would probably shake the format up well enough to restore interest, but Mystic is probably still a central card to the format.
There are a few cards in Legacy which might warrant unbanning, Earthcraft and Mystical Tutor the most prominent among them, but given how recent Misstep's shakeup of the format is, it's unlikely that Wizards will follow through on it.