I'd like to see them not all be below ground.
I'd actually say that's a good idea. It seems to be a common cliche in fantasy games that any dungeon needs to be underground, even if your dungeon is supposed to be some above-ground statue like a castle or tower. For once, it would be nice to see some dungeons located entirely above ground, and where going "deeper" into them means going up, just for variety.
I wouldn't mind some really large dungeons in the game too, not every dungeon needs to be a sprawling, underground labyrinth that you could take days to explore, of course, but some dizable dungeons would be nice, and most importantly, we need less generic dungeons, because after a while, one dungeon started to feel pretty similar to another in Oblivion. The Game Informer article seems to promise this, I hope that the game delivers what's promised too.