Well, suppose there's a replacement for Power Attack that works in a similar fashion, but with a fixed amount, as others have suggested.
It's not a reduction of choice when building the character; you still choose whether to take the feat or not.
It's not a reduction of choice when fighting; you still choose whether to use the feat or not.
I suppose one could call it a reduction of choice, in as much as it's no longer possible to decide whether to PA for a little or a lot--but honestly, that doesn't strike me as a real loss. The capability is still there, and the ability to play a character who swings wildly to hit harder is still there. I don't think that the loss of a small bit of granularity--and really, that's all we're talking about here, a tiny matter of degrees--is too much to pay for a more streamlined combat.
(Granted, this assumes there is an equivalent of PA in the new game, but I think it's likely.)