Few things are more fun that Fell Cleaving the crap out of something. So war's been a ton of fun so far in the MSQ.

But I'm liking the Dark Knight too. Lotsa fun balancing the MP and Proc skills are always fun. The naysaying on their defense seems a bit overstated.
The exception being that Shadow Wall is on a longer cooldown than Vengance while having a shorter duration and no extra effect. Or, alternatively it does 3/4ths the mitigation of Sentinel but has no advantages. Something should change there. Shorten the CD to vengeance level at least.
Dark Dance, IMO should Dark Arts into some kind of guaranteed reduction.

I do wish the Darkside effect wasn't so huge.