Isn't this the entire solution? I know I'm not the first one to have thought of this and expect there's something I'm missing, but I've been brutalizing things as 5x kitty form druids from 20 to 33, and don't see the downside. I'd be running off to try it with a team of DKs or rogues right now if my RAF wasn't a week away from expiring. I have a melee attack macro that basically goes:

/follow focus
/startattack [target=focustarget,harm]
/cast Tiger's Fury
/castrandom [target=focustarget,harm] Claw, Shred, Rip, Rake

The leader has to move around a bit to keep the mob between him and the alts, but there is never really a time when any of the alts stop DPSing. I spam the attack key and stuff dies.

btw, multiboxing cat druids is more fun than a really fun thing. I wish I had speakers on this computer, because the cacophany of claws, shreds, rips 'n' rakes shrieking through my headphones would probably sound even better were they really loud.