I hate the idea.
When I'm dps i hate going in because i don't wanna get unlucky and killed by Unknown.
When I'm healer i hate this idea because i don't wanna raise a dead dps flushed out of doggie's belly.
((When I'm tank, well it's none of my business. But generally speaking, dead dps = less damage = longer wait = more chance to mess up = potential wipe))
So yeah.
And quite frankly, it doesn't really speed up the phase by a whole lot. And alas, wolfsbane will go wild outside of belly.
Don't have a suggestion or solution to this, but when I'm tanking, I usually go in belly along with many DPS and tank the Unknown while DPS are killing stomach. Might pop a couple CD but it's worth it. No dead DPS, everyone's happy.