Hi,
One thing I've missed since classic, is a 5 man dungeon that's quite big, and have different "wings".
Take Stratholme for instance, it's a pretty straight forward dungeon if you don't want to make a big deal out of it, but If you want, there is a lot of stuff you can do (Scarlet side, postmaster, etc) and I kind of miss this.
After TBC all instances as I can recall have been pretty much straight forward, one path only, and that kind of sucks.
I would love to see more like this in Cataclysm, even tho I seriously doubt it will be implemented.