I've assumed from the start that Bhutto was sponsored by the US to depose Musharraf, who was not behaving on his leash as he was supposed to.

Remember that a world leader with nukes does not have to kowtow to American interests.  It is clear that Pervez was not exactly towing the line for the Cheney folks.  I'm sure if I google Bhutto's recent comments there is a free-market angle to be found.  She certainly did not represent the poor and destitute of Pakistan, that is for sure.

I also think that Bhutto's presence has generated a huge amount of instability and she was taken care of to REDUCE that.  Ultimately the opposition needed her to rally around, to give it some kind of legitimacy and a tie to the "old days of Democracy" in Pakistan.

From what I've seen and recall from his takeover, Musharaf is really not some Hussein-esque dictator.  He took over a corrupt country from a corrupt leader and the nukes probably had a lot to do with it.  During his term Pakistan has largely avoided major war and skirmishes with India and other neighbors.  

If you can look past the "democracy" red-herring it would appear that he's their most competent leader in a long time.  I certainly had no hope that Bhutto's faction would do any better.