Thanks for playing, and glad you liked it!
Yeah, the dungeons definitely needed some more love, but after polishing the combat, not much time was left, I just barely got in enough dungeon floors that the 5 levels of encounters I had (somewhat) balanced had a place to live ^_^.
Final boss probably could have been harder, although for the most part I was thinking of clearing the floor before as the "final boss", and defeating the actual boss was just triggering the narrative ending, but I guess that just felt like a bit of a let-down. I really didn't want a party wipe and people to have to re-do the final floor though, if they got that far, as it was already getting long =).
As for backtracking to level up, you may not have noticed you can click on the map to move to where you've already explored, makes getting back to Solitude painless.
I'm also not sure on the constant renewal, had the endless stream of replacement adventurers not been our primary "endless" theme idea, I probably would have done something more traditional there, though I did like being forced to use different skills at times. I think if I were to expand this into a fuller game, it would treat character replacements similar to equipment - you find someone new and decide whether or not to swap out an existing party member or something.
The enemy types were fixed on what they used - basically there was an armored/balanced/hp sponge/damage/aoe enemy type for each floor, and they were always the same. The in-world enemy sprite you see just represented an "encounter" (usually containing 2 of the variety you see, and one other), although since each encounter was only seen 1-2 times in a floor, it's not something you'd actually really discover (or, if you did, you'd likely not change any behavior due to it ^_^).