Well, Miller's already better than Bruce, if you think he can keep doing it. He's certainly younger/less injury-prone (and I realize you don't literally mean bring back Bruce).
Gonzalez can also be a pretty big bat, if not an all-around productive hitter, assuming he isn't as bad as he was last year.
In both cases I feel like they are already focusing on LF/1B guys, it would be a small bonus if they can play a little middle IF, but they're neither Josh Harrison/Neil Walkers who are definitively 2B/3B, nor SS candidates.
I agree anything can happen with Kingery, but A) he's probably going to be our opening day centerfielder (against a lefty) and B) if they weren't expecting him to play a lot of OF we really wouldn't need Maton or Chatham. But every manager seems to want one more bad-hitting glove than any fan does.