I will not buy into the premise that Musharraf's government will collapse if we were to lead offensive operations into the FATA. I am not convinced whatsoever. We have asked, cajoled, threatened, and requested that the Pakistanis do it themselves and they are incapable of long term sustainment in that region. I don't want to argue why they can't do it themselves but rather lets address the real problem -- our enemy finds sanctuary inside the borders of a supposed ally on the Global War on Terrorism.
What sort of offensive operations are you talking about? Are we talking about the 82nd Airborne or I MEF setting up shop independently in North Waziristan and basically occupying the area?

If so, I think you'd be hard-pressed to find any Pakistani government that could survive under such circumstances.