Just finished raid tonight with a high haste build (13157 haste), did really well and it felt really smooth and fast. I think the 2 and 4 pc set bonus is what is bringing haste up and crit down.
I ran destro on our hc protectors and had a 8.5% uptime on destructive influence, and a 33.7% uptime on ember master. This effectively brought my crit % way up, so far up infact that this is what my %s were:
Immolate: 40%
Incinerate: 40%
Conflag: 44%
My base unbuffed crit for tonight was 18.5%.