What specifically do you have in mind? I'd like more difficult dungeons, but the 1-50 stuff doesn't really stick out to me as something to base future dungeon design on. In my opinion the fun off FF14 comes from pulling off your rotation under stress. Puzzles and clicking switches don't contribute to that and I find that they can very easily break the flow of content. There are ways to add them to dungeons that can be fun, so I'm not against them completely. I just don't find anything interesting about eating fruit every minute in Aurum Vale, or standing in AoE's in Dzemael just to progress.

I'd like to see branching and especially randomized paths and enemies which would add more replayability and prevent me from memorizing a dungeon. I'm not opposed to crowd control either, but I don't want it to be something like "cast sleep on this enemy or you fail". Many crowd control skills were considered useless in SB but I really liked using them in desperate situations. These would only pop up 1 in 100 dungeons runs but that's part of what made them rewarding. They were useful in rare occurrences and you had to rely on your experience and skill to make them work.