If you don't get a hunter for chog'all and magmaw perm, you will need to ensure you have 2 solid high aoe ranged classes with slows and snare otherwise you will bang yer head on the Cho'gall fight going into P2 with way too much corruption, and never down him.
As an example the only time Jagger failed to down Cho'gall when on farm was when I was stuck pugging to replace Moonkin and Sagenn. I got a rogue and a mage sub-15k and we were still getting raped by the bloods getting to raid not being killed. The whole Cho'gall fight is about add control, it's one of the only fights makes strong aoe and slows/snares mandatory. YJ specifically spec's into survival as it's the highest aoe dps spec and the 2 pt talent for 4s trap snares, I've heard mages can cover but the fight is 100% more simpler and less stressful with a hunter doing the job.
Being a hunter is hard....