I've been playing quite some time now (achieved my goal of 500K in expert mode, going for 1mil), and here are some things I've noticed/thought might be nice:

-highlight your score in high score list, since my name is always the same and I don't remember my exact score I'm not always sure where I placed in the list (I'm just trying to outdo myself)

-auto-use health: in the expert mode it would be nice to have the remaining health potions used before going to the next dungeon (i forgot sometimes and have little health)

-9letter+ word option (for those infrequent occurences)

-sanity letter selection: I sometimes get letter combinations where the possibility for words just isn't there. It would be nice if there was a filter that determined if it will actually be possible to "reasonably" finish a round with the provided letters

-letter discard: particularily in non-expert modes those extra letters are sometimes hard to get rid of (especially Q)

-no double dragons! in expert mode this happenchance of bad luck almost is certain death (that is, only one dragon max in a dungeon)

-single dungeon score stats: most points/damange done in a single dungeon

-power mode: start with more letters, but words of less than 5 (or 6 maybe) do no damage

One last thing, please add the word "****", I end up yelling it at the computer every time it doesn't accept it...