I've tried this, and I thought I was doing considerable dmg, until I compared my own dmg, to a single DPS.

Wasn't even close.

In the span of 3 GCDs, I did roughly 5% of the dmg a single DPS did. (After all DoTs are on the target)

I still do it, but its not all that impressive in any shape, unless its content you're over geared for.