First, on FL in Reveler Delver decks: it just doesn’t do enough. It puts us down a card, and the flashback cost is really hefty in a deck like this. Instead of reasoning that we “don’t care” about losing cards because of Reveler, I’d rather trade off my cards one for one with my opponent’s and then pull way ahead instead of just a little. Looting will also pretty much lose us the game if we don’t find Reveler eventually. (For the record, I did test it. Looting is one of my favorite cards :D)

Second, on FL in this deck: The Monkey Grow core is so tight that we just can’t fit a Looting. The main reason to play this deck over the Reveler Delver decks I first brewed, which had Bedlam in the main, is that Monkey Grow smashes Modern’s linear decks. Diluting the core would defeat the purpose of playing it at all. So we’d have to play FL in the sideboard, and as evidenced by the article, we really don’t have room for it (not that we’d even want it!).

If you understand its drawbacks, I guess I don’t have to explain Dismember to you. For the record though, I did try it numerous times, as it’s one of my favorite cards in the Modern pool. I’ve linked you to a couple examples that were published on this very site, one from last year and one from this year:
http://quietspeculation.com/welcome-to-the-jungle-mandrills-in-modern/
http://quietspeculation.com/carpet-shopping-building-rug-delver-in-post-twin-modern/

As I said there, I brewed the UR burn deck the morning that article was published. I also don’t like it, which is why I didn’t chase the thread. I also tried a more interactive UR deck with Shoals and just didn’t like it as much as I did with Tarmogoyf. Goyf just fits so well into interact-while-attacking URx decks in Modern, and Traverse’s synergy with the Reveler is another huge draw to the green splash.

On another note, I disliked your burn take on UR reveler, but I tweaked it a bit to make it a shoal deck and I have been loving it. I have always been dissatisfied with the card disadvantage in modern and have always defected to traditional staples like spell pierce and what not, but mad reveler solves the problem and since you are incentivized to use it early to clear your hand for reveler that shoaling any turn 1 play feels amazing. It’s built like you would think but replaces guide/dedicated burn with shoal and interactive burn like pillar and forked bolt. Thank for the idea

A turn-one Gitaxian Probe enables a turn-one Spite for 1 damage. As he said, it’s rare, but unlike with Roast it’s at least possible.

Spite does seem interesting in a shell with 50% i/s.

Nope, you’re reading correctly. But unlike Roast, Spite at least has the possibility of killing a dork on turn one, whereas Roast does not. And between Traverse, Probe, Serum, Shoal, Bolt, etc. it’s pretty rare that a turn two Spite won’t kill an x/1.

Roast is better in certain early games, but I’d argue that spending two mana and a valuable removal spell to deal with Hierarch is awkward more of the time than Spite not having enough i/s in the yard is.

PS. Good write-up. I look forward to going back to Grow!