I'd be down for more types of content. I think they have a lot of room in between current dungeon design and savage/ultimate. Current content lacks teeth. Challenging 4 man dungeons or even full boss encounters would be cool. You could even add in 8 man challenging dungeon. It might open up encounter design a little if you had a zone to work with.
I disagree though with race against the clock. Obviously that shouldn't be the default, but if it fits for the encounter and is more than just zerging I think it could be done well. I still remember doing 45min Strat runs in WoW before everyone had gear and that was pretty fun!