At the risk of being terribly presumptuous, I'm going to guess that Cameron's not suggesting the Red Sox would be better in 2011 with Beltre instead of Gonzalez. What he's saying, I think, is that Gonzalez just won't be as valuable in 2011 as Beltre was in 2010.
And I think he's right. Beltre was fantastic this year, a fine hitter and one of the best-fielding third basemen in the majors. Add everything up, and Beltre was probably one of the five best players in the American League.
Adrian Gonzalez wasn't quite as valuable in his league. He's certainly been more consistent than Beltre, and there's a pretty good chance that he'll be more valuable than Beltre next year. At best, though, all Gonzalez does is replace Beltre's lost value. And he probably doesn't do that, considering that the Red Sox will probably go from having outstanding defensive players at both first base and third base to having merely adequate players at both positions (Gonzalez is fine, if often overrated, at first base; considering his bulk and relative inexperience, we can't expect Kevin Youkilis to play brilliantly at third).
Dave Cameron is right: Gonzalez isn't an upgrade.
Fortunately, the Red Sox don't really need an upgrade. A replacement (or near-replacement) is fine. The Red Sox' fates hinge on their ability to stay a lot healthier than they did last season. If they're reasonably healthy, they'll win 95-odd games. If they're decimated by injuries as they were last year, it won't matter who's playing first base (or third).
But they couldn't just sit on their hands this winter. They gave up two outstanding prospects to get Gonzalez, but when you're trying to win 95 games every season you'll occasionally have to give up an outstanding prospect (or two). I'm sure it hurts the guys in the front office a lot more than it hurts us. Once you pick up a couple of World Series rings, though, it's hard to give up on another, even if for just a year (or two).