1) On cataclysm... well, this wasn't successful one) Tanking trough HP doesn't work balanced enough (at least i didn't handle with it), even with Healer druid behind. There was a tanking trough resurrection (druid is great here).
2) 1st shot for druid... a bit dissapointed. Pros - In terms of numbers it is probably the best healer at the moment. But the gameplay is kinda weird. Melee version - doesn't work at all for me, kindred spirit died in 2-3 hits. As a caster - A LOT of concentration.
3) Saying a lot - Swift blade is the best subclass of this add-on (and one of the best in compete with all dd subclasses).
Really. Who can beat it? Blade dance+hunters mark+poison+aura of righteousness (if get one) saying good bye for every target fast enough, but mostly shines on bosses - bottle neck of many fights. If you have a great competitors as melee dd - please, share it!
As a result - not enough tanking potential (even with a court mage)
Now starts with pally as a tank + cleric. Goes FAR MORE easier.