[dang it], I wrote most of this post once and somehow lost it.
Anyway, I agree with almost everything Roy said, except about Bosh playing some good minutes at center. He can't start at center. However, maybe it's time the 7 foot Garnett, whose mobility will quite possibly no longer be what it once was, made the move to starting center. Despite that one issue, I'd do this trade in a heartbeat. There are some things I'd rather switch out - different pieces instead of Perk, something other than Graham - but I'm just shocked nobody's mentioned there's no way Toronto does this trade.
First, I don't think we lose anything at the point. In fact, I think Calderon might be better than Rondo now and for the future. Calderon is a pure point with great distribution, a ridiculous A/TO ratio and a great shot from all parts of the court. His defense is not good. However, and maybe I'm wrong here but I feel that good players have a much stronger tendency to develop defensive skills (which can be improved through increased effort, conditioning and understanding of team philosophies) than to develop an outside shot (an individual skill based on mechanics).
Look at how Ray Allen and Paul Pierce improved their defense markedly over the past two season. Christ, look at how JJ Redick pestered Ray Allen throughout that Orlando series. I think a big defensive improvement is particularly possible with Calderon who already has excellent height (6'3"), length and quickness for his position. He needs to improve bulk, but he has a lot of room for improvement.
Offensively, as much as I enjoy Rondo's game, Calderon's shot just makes such a huge difference that I'd strongly prefer Calderon on that end. He could be more aggressive, but that's mentality, not a lack of an actual skill. He's already ahead of Rondo on that end, and could get better. I think Calderon was affected quite a bit by having played for the Spanish national team last summer and I'm not overly concerned with his health.
What's more, Calderon already is locked up on a reasonable contract (4 more years, $37.5 million). While a similar contract for Rondo might give me more pause, I think Rondo is gonna be looking for something more like 5 years, $50-55 million minimum. Either way, neither Rondo nor Calderon is going to be a top 2 guard ever (neither will catch Paul or Williams) and are both probably gonna remain in the second tier. Without much difference, especially since Rondo may have a fundamental flaw, why not take the guy who's locked up reasonably instead of the guy who may be trying next year to cash in on having been the point guard on a championship team (or hopefully two)?
With Ray going, we lose a lot. And I just don't like Joey Graham in any way, shape or form. The trade works salarywise without Graham, so I'd just as soon not include him in the deal. It's not like it saves Toronto any money (they can just let him walk) and he just wouldn't help us. If it was a one year deal at the QO level or lower, I'd be fine with it, as his expiring contract could be used around the trade deadline to add somebody of substance. We'd clearly have to find somebody to start at the 2, but the acquisition of Calderon's shot makes the loss of Ray's shot less of a problem and allows us to target a guy who's got a decent shot but can give us better defense.
Finally, the big men. I love Perk and overrate him. And having a true center can't be undervalued, particularly with Howard just coming into his own in our Conference and the potential to see Bynum frequently down the road. However, Bosh over Perk is a bigger upgrade than Allen to Graham/TA(who I hate)/House/Giddens is a downgrade. No doubt. It would make finding a center imperative, that's true. But it's worth it.
The fact is, Bosh is a 25 year old perennial All Star power forward. I think Bosh is a bit overrated, mostly because I think the fact that he gets lumped in with Lebron, Wade and Carmelo (simply because he was from the same draft class) is a huge exaggeration of his talent. However, he has a very good offensive game - solid finisher around the rim, gets to the line a lot and hits free throws, knocks down long jumpers with some measure of consistency, rebounds adequately (not great in that department, but good), a little weak with post defense (which is why I think Roy is wrong on the center argument) but very capable of defending perimeter-oriented bigs due to his quickness and athleticism.
Losing Perk would be a blow because he's ideal next to both Garnett and Bosh, as he can take the physical pounding those other two can't. But like I said, the upgrade to Bosh is so big, I couldn't turn this deal down.
I would strongly prefer if we could make this a sign and trade involving Davis or Powe (though I'm not sure Toronto would want either rather than Perk). For that, I would throw in Giddens, Walker, basically any young player or draft pick Toronto wanted and would even take on, say, Marcus Banks' or Jason Kapono's two remaining years. A frontcourt of Pierce, Bosh and Garnett with Perk coming off the bench would be phenomenal (arguably, you could start all 4, putting Bosh at the 3 more easily than you could put, say, Amare there but it's more likely Garnett would start at center and Perk would come off the bench, with Perk starting against Orlando). That would be a real New Big Three (which to me requires it be the two forwards and center, my biggest problem with KG, Pierce and Ray having that nickname).
Keep in mind, the preceding has really been focused only on the present. For the future, the improvement is incredible. Anybody who would rather build for the future around Perk and Rondo (as much as I love those guys) than Bosh and Calderon is just plain nuts. Bosh is your heir to Garnett. Not as good as KG obviously, but you keep an All Star big man to build around, with a legitimate third option point guard, and they're both in their 20s. They'll need a number 1 or 1a option at the wing (an heir to Pierce) to be perennial title contenders, but Perk and Rondo would need a Lebron type to be perennial title contenders. This would be a good foundation without costing anything substantial in the present.
Like I said, a good 2 guard who can defend and shoot is necessary, and we'd still have our need for a 3/4 backup, but this trade would improve our team radically.