Not a 7/7? Is his ability that good that it meant needing to shrink him? We'll have to see. This is obviously a solid Commander, although people are learning to play removal spells like Terminus and Hallowed Burial, this will hose decks that can't play white and will allow you to run those spells with impunity. Expect ridiculous foil prices, expect these to trade well and expect the presale price to be too high.
You know what deals with Indestructible slivers?
Aether Twister looks like a bit of a blowout. It's easier to play around than a card like Hallowed Burial, but it lets your opponent make tough choices, which allows them to make bad decisions. I don't think this will be a ton of money, but with Mass Calcify looking like it's going to occupy to Day of Judgment slot in the set, it may be necessary. I think we'll lean on Fated Retribution a bit, too, but this could be a $5 card under the right conditions.
I guess Viridian Shaman was OP. Who knew?
Stain the Mind
I expect this to get less play than did Slaughter Games and to have less long-term price viability to boot. All this card did was remind me to buy a bunch of Slaughter Games when they rotate. Standard demonstrated that as currently configured, it doesn't want this effect and older formats have demonstrated they don't want to play 5 mana or tap their dudes to get this effect at sorcery speed. All in all, this is a bit of a whiff.
That said, mono black sure is getting some gifts. If it decides it wants this effect, this card could see $2 or $3, but it's likely relegated to sideboards which hurts it a bit.
Remember when Cranial Extraction was $20? Crazy days...
It had to happen. Either they print another one and reduce the value of an older variant, likely Grindclock, or they reprint Grindclock itself and lower its value. The only way clock's price was safe was if they reprinted something else like Sands of Delirium. This card will be clunky as heck with no Proliferate so I expect this to see 0 standard play even with Phenax, God of Deception whispering in the ears of the guys with the "My Little Pony" sleeves and topless anime chick playmats.