I'd have to agree, our guild is doing 16 man at the moment. We killed Toth and Zorn 5 different times with different 8 mans (clear it with one set of 8, then rotate in a few) in order to practice it before all 16 logged on.
We spent 1 hour on 8 man Toth and Zorn before we downed them then /stuck on the handler to that we didn't lock ourselves out.
In total it took my 16 man ops group 8 hours to down Toth and Zorn. 16 man seems to be in the right place, it's 8 man that's under-tuned.
Do not want a nerf. Make 8 man harder. It's supposed to be a nightmare!
It WAS supposed to be a nightmare until Bioware decided to mess things up and make it required to get the next tier of gear, completely destroying the purpose of nightmare raids (being insane, optional and very challenging).