Just to add to what arduin said you really shouldn't have too much of a problem depending on who you have with you raiding. A few rogues and hunters are usually more than enough to keep the boss from turning around and pasting you to the wall. That said you being able to close a 70k threat deficit in 20 seconds is actually quite impressive. So assuming that you are doin the right thing (because in my opinion kitty isn't really a rotation as it is a prioritizing from most to least important depending on the situation) by the ammount of threat your raking in, it might not be your problem so much but more the rest of the dps/tanks. Maybe if you talk it out with your MT you might find a solution, or it is possible one of your dpsers who could be MDing aren't because they don't realize its needed (which happens more than you might think).
But to directly answer your question agro usually isn't too big of a problem with kitties, however there are a select few of us who bosses seem to love just a bit too much.