Try Dungeon Hunter 2. Still the best dungeon crawler on the AppStore, far superior to its sequel or Chillingo's Orc game.
I second this. We really need someone to dethrone dh2 for best diablo clone, it's time to man up devs. make the combat like dh2 but expand on it. Orc was a great try and a good game, but one shotting every enemy one after another with the same basic attack is not good for longevity. here's hoping the infinity blade diablo will be that game.
DH4 ftw...I doubt GL will mess it up like the 3rd one. And other devs don't have the experience or manpower to do it besides Chair, however I believe Dungeons will be mediocre at best, unfortunately. Chair just seems to oversimplify things when it comes to controls, and while that's great for IB, I sure as heck don't want gesture and tap to move controls for a dungeon crawler. We shall see, really, as I'm totally speculating at this point.
Dungeon Defenders. NOTHING else in the app store even remotely comes close to it in terms of the amount and variety of loot. Oh.. it is also more or less a full port of a PC game (minus all the new dlcs and some balancing issues) so expect a really fleshed out game with a strong cross platform ( with android) multiplayer experience.
Dungeon Defenders is nice but i had it crash more than a dozen times while playing online, both game center and gamespy. Although it's still on my 4S til now lol. There's this upcoming game by CM games and they said it has "loot" so hoping this will be the one to take DH2's place. But as of now, DH2 is still the way to go i think
A game with droppable loot. I would definately take a peek at Pocket Legends, Star Legends or Dark Legends. They have droppable loot in different rarities, and are awesome Free-to-play Loot dropping MMO's!