I think it is possible to separate your prior work with your current one. One of the many reasons we have things like non-disclosure agreements and what not. In this particular case, with the fact that the debate management itself was poor to begin with, it wouldn't have made a difference if Stephanopoulos was being partial to Killary or not. Nothing of substance came out of it until the end, and even that was weak. Of course, with the way many of the pro-Obama moderators in prior debates conducted things, it would only be "justice" for Killary to get a little bonus for once.
So.. as a deep hypothetical....
Assume for a moment GWBush could run for a third term and choose to do so...
Would Karl Rove, who held an aproximately equivalent position for Mr. Bush as Mr. Stephanopoulos held for The Clintons, be an appropriate moderator?
Actually, by and large Stephanopoulos is actually less partisan than many other journalists.. but you gotta admit the notion of Karl Rove as a moderator is pretty absurd.. why is Stephanopoulos any less crazy?
As I said, it's possible to separate your prior work from your current one. No one that sits in that chair is going to be free of bias and/or favoritism, even if you've picked someone who is registered in a different party and no care about who wins the nomination. For the parts I watched, George did an ok job, at least much better than Wolf has done. And, as far as Karl goes, George isn't as cerebral as Karl, so he couldn't scheme a whole debate in an attempt to trap someone at the end of the debate as Karl might. Two different beasts all together.