Viable? Maybe. Your threat will be less and slower to increase meaning your raid’s dps will have to more closely monitor their threat. That’s a bigger issue with Horde than Alliance. Druid tanks are prized for high threat gained quickly. MCPs are the reason for this you’re gimped without it.
Feral dps drops off by a good amount without MCPs. Easy farm.
Why bring a non-MCP using feral? Their mediocre threat and their dps won’t even half compete with a rogue or warrior. A MCP-less feral in progression is a wasted spot.