YP mentioned somewhere "We're happy with the DD model"... so I'm afraid the next one won't be mechanically distinct as many would have hoped for.

Maybe that's why they decided to go for "going horizontally" rather than vertical floors? Just to give the impression that the formula was shaken up.

I wanted to actually see different map designs rather than just the same map with square rooms next to each other.

Ditch pomanders for a completely new power system. (Ironically I think Phantom Jobs would be a fine system for a Deep Dungeon if they were a little more fleshed out)