Answer to question = as of Game 1 of this season.
Not only is he in the way of the rebuild, but Spencer is ready.
We will be weaker up front in the shrot term because of it -- for the first time in half a decade we have size and depth up front. But its a short term mirage anyway. That size and depth is aging and depreciating in a season which does not matter. Get what you can for it (Brad and Mikki) while the getting is good, get them out of the way of the kids, bring back in a little more young talent, and now that the rebuild is finally here, lets accelerate through it. We've got a young core that can be competitive in a few years with Kevin/Spencer/Thompson, and maybe Greene, Beno, or Cisco. So time to get the pieces that will actually be able to play alongside them.
I was ready to push Miller off the bus last November when he came out guns a-blazin'.
Of course it would make us weaker for the rest of this season, but the tradeoff is that you develop a guy who is, if not ready, he's ready to get ready and is the guy you've tabbed as the future holder of that position, and you clear cap space (presumably), and you send a signal to your fan base that you're serious about building the team the right way. I think the Kings front office has signed off on the idea of losing a few games for a couple of years, with an eye on the future.
If your core is going to include Spencer Hawes, then there's no reason to keep Brad Miller around any longer than necessary. He had a pretty good year last year, he's playing at about the same level so far this year, and there are a number of teams who could use him in some capacity to make a run now. He's 32, won't get any better than he is right now, and makes a ton of money for what he is. I don't think his value for us is such that he's not already expendable. I'd say he's been expendable for two plus years now.
And we all know how I feel (and have felt) about Mikki Moore, since the beginning. No need to articulate it again here.