Essentially, to-hit appears to be largely meaningless so I'm thinking that makes Power Attack more of a no-brainer than it used to be.
However, hitting on a 2 appears to be a thing of the past, so I suppose it boils down to whether or not Power Attack costs you a single "to hit." As in, fighting normally you hit on a 4, but with PA on you hit on a 5. In such a situation, you'd be better off turning PA off, right? But isn't this essentially the situation for everybody at all times, now?
So I'm thinking PA may actually become worthless. No, worse: counter-productive. Is this the case, do you think? Any math that shows your work would be most welcome.