The only problem I've had with mana issues is Stonecore. And despite having said so at the very start of the dungeon have experienced tanks rushing forward.
Mana becomes a huge problem in such a dungeon since your average dps'er soaks up all damage from the whirlwinds, and on top of that gets that dust crap thrown around once in a while. Often the tank doesn't really care and have pulled the next group before I can even get a chance to write MB :P