Just an FYI, there are times that a sufficiently beefy DPS Blaster will literaly TEAR aggro off of even tanks.
Not OFTEN. But on occasion. Had this happen with a couple of experienced tanks on a Tank, Blaster, Tank team when I was, strangely, rocking a Blaster.
I kept getting a huge chunk of the aggro turning around and whaling on me.
At first, I thought I wasn't giving the tanks enough time to aggro grab, and thus was drawing the alpha strike.
So I'd sit back for a moment, let them go in and engage, then let loose.
Yet again, "MACROSS MISSILE MASSACRE!" *OOH! NUMMY FLOOR!*
None of us could figure out what was going on.
And if I had to sit there and wait for half the spawn to die, there was no point in playing...