Garnett is too old to play the 3.
IMO, McDyess looked as good as ever last season. Sheed, on the other hand, looked pretty much finished as a top player. Him and Nesterovic can't defend the younger, mobile big men or the dribble penetration any more.
McDyess may be similar to Baby, but he's a much better rebounder and post player. Of course, we'd need someone else to defend the post. I think I know an excellent fit, but it's a long, long shot
I don't agree with that. Aside from the injury, Garnett really hasn't shown sides of fading athletically. And the injury could've happened to anyone. Moreover, I'm not suggesting that Garnett play the 3 for 40 mpg. Rather, I'm suggesting that he could get 5-10 mpg there, particularly in the playoffs. And really, it could just be a playoff thing; because during the regular season the C's could get away with playing Tony Allen at the 3. They're going to win 55-65 games next season with whoever they have on the bench.
As for Dice, I agree, he definitely plays bigger than Baby. I think Dice could definitely get backup 5 minutes, particularly if KG is on the court with him. He'd certainly be a huge upgrade over Powe or Baby at the 5.