All those people who were calling for POB are now witnessing that he can't crack the rotation in Toronto either. Maybe Doc is a lot better at gauging when a player is ready to help a championship caliber team win games, day in and day out, than many thinks he is. A few fancy dunks and a good NBDL game aside, Walker and Giddens have shown nothing in games and probably just as little in practice. Let's face it if they want minutes they have to play better than the people in front of them.
Doc has done a masterful job of keeping the Big Three's minutes down while at the same time winning games. As I posted elsewhere, comparing the amount of minutes he plays the Big Three as compared to the minutes that Popovich, Jack, Tomjonovich and other championship coaches have played their 30+ stars you will find he plays them about the same or less(sometimes much less) than those great coaches played their thirtysomething stars.
Doc says they aren't ready, his track record since getting some talent here in Boston is okay by me. I think he's earned the right to play whoever he wants.
The first half of your post is well-taken; the second half I disagree with. You mentioned that Walker and Giddens need to outplay the men in front of them to get time, and I agree with that. Paul Pierce and Ray Allen are undoubtedly in front of them, and then there's... who? For the third time, what happens when Paul Pierce can't play due to foul trouble? Do you put Ray on LeBron for 36 minutes of the game? I sure hope not. Again, what if we
have to put one of the rookies on the court in the playoffs?
And I disagree that Doc has done well at keeping the Big Three's minutes down, with the exception of Kevin Garnett. I think Ray and Paul have played too many minutes, especially here lately. It's one thing if they have to be left in to preserve the game, but it's another thing when they're left on the court in a blowout. In the 38-point win over the Nuggets, Paul and Ray played 33 minutes each, more than anybody else on the team. You can't tell me they couldn't have been pulled earlier without jeopardizing the win. In a 20-point victory at Phoenix, Paul and Ray played 44 and 40 minutes respectively. The whole "Phoenix can close the gap really quickly" argument is bull. Pull them, and if Phoenix goes on a run then put them back in.
Doc has indeed been a great coach, and I think he got snubbed last year for the Coach of the Year award. That, however, doesn't mean he's immune to mistakes, or that his judgment can't be off. I think this is one of those times that his judgment is off.