At this point, I don't think it really is. The best predictor of future performance is recent past performance. For better or worse (that is the only subjective part), what Bendis does is destroy things done on the series he takes over.
When he took over Avengers, he destroyed what came before.
When he took over Guardians of the Galaxy, he destroyed what came before.
Thankfully, there were alternative X-Men that kept the destruction to a minimum in this case.
It only stands to reason that whatever DC series he gets, he WILL destroy what came before if he's given enough control.
If he does half as good a job with Superman as he did with early Ultimate Spiderman, we're in for a heck of a run. But keep Superman powerful. Otherwise forget it.