The only way to keep up on damage in MC/BWL is by power shifting and that leaves you with no mana for battle rez or innervate.
Innervate costs 50 mana and Rebirth costs like 1k, this is by no means a problem. Bring a few demonic runes just in case you're completely OOM when somebody needs a B-rez.
Feral druids are alright, you just don't want to bring several. One feral druid pulls their weight just fine. In terms of sheer efficiency and power, they're not a disadvantage the way a lot of other ill-favored specs are.
I think it says a lot about Exiled that they're unwilling to bring any spec that isn't viewed as optimal. Those will be some boring-ass raids with 15 frost mages and 8 combat rogues. Sounds like a terrible guild environment.
Plus they can throw on tanking gear and be a better off tank than a feral druid (only because druids get practically nothing for tanking gear in MC/BWL while fury warriors get tier 1 and tier 2, which is amazing gear)
A fury warrior is definitely not a better OT than a feral druid. Patch 1.4 warrior tier gear is also pretty bad (the entire warrior T1 and T2 sets have precisely zero defense on them), like it is for most classes. Most people will be wearing a large portion of their pre-raid BiS throughout all of MC, except maybe rogues and hunters.
People will be sorely disappointed when they see Nostalrius' 1.4 loot, and it seems even top guilds aren't prepared for what this does to class balance.
Feast your eyes.