Completely agree - sadly the 'top 25' lists are autogenerated, and anything listed as part of a genre qualifies … even add-ons!
It really is disappointing that the "RPG" category on the App Store is absolutely laden with these "Buy 50 more points!" microtransactions for dozens of text-based "buy your way to the top of the food chain" applications. I'm not even sure why they're classified as games, since as far as I can tell there's no actual gameplay and they're basically just ladder boards of how much of a sucker you are in comparison to the other suckers who are paying to make their respective ways up the virtual ladder.
That said, I suggest that you folks who are enjoying Undercroft also check out "The Quest". There are several threads here on the board where we've discussed it before. Similar to Undercroft, it's a more traditional western style RPG using the old Wizardry-style 3D blob movement with turn-based combat, heavy on stats, customization and dialogue. Unlike Undercroft, it's a single-character game, where the customization system is quite similar to Daggerfall, or the other Elder Scrolls games. Your character can develop his/her skills in various weapon categories, magical schools and alchemy, thievery tasks, persuasion abilities, etc.
It's a huge game, and there are currently four expansion packs available for "The Quest", with at least three more on the way. There's currently well over 150 hours worth of content available, if you enable all the expansions. The expansions can be played as stand-alone games, in addition to being incorporated into your main game, if you want to play each one with a different build.
There is a Lite version available for free, and the latest expansion pack is free this week as well (which can be played as an independent game) if you want to get a feel for the game. If you decide you like it, there is a Gold pack version ("The Quest Gold") available that includes the base game and the first three expansions. Combine that with the free for this week fourth expansion, and you've got hundreds of hours of gameplay for under $10.00.
Here's a link to a big thread on the game at TouchArcade, in case anyone wants to learn more
http://forums.toucharcade.com/showthread.php?t=5492.