Second round picks he's either traded away hastily or wasted. Acy might be a bench player. I'd give him a D+ for his handling of 2nds.
Trades he's tended to overpay. Took a bold gamble on Jermaine O'Neal but gave up too much. Still, Hibbert was never going to be the pick if they had kept it.
Marion deal was bad, helped Miami build it's mega-powers.
But, he's managed to find overlooked gems in a lot of his moves (Amir Johson, Sonny Weems, Jerryd Bayless, James Johnson) and he dumped Hedo in a heist
As long as the pick surrendered to Oklahoma isn't 4 or 5 (and maybe even if it is considering how bad this draft is), I still like the Kyle Lowry trade. If the pick is 6-10, it's a very good trade. Lowry is Toronto's best player. You have to give to get.
I'll give him a C- for trades.
Free agency has been troublesome, with the caveat being it's extremely difficult to lure players to Toronto for various reasons. You almost always have to overpay free agents and Toronto is one of the 23 or so cities where that is especially true.
Anthony Parker, Jorge Garbajosa and Jarrett were great signings. Kleiza was OK. Jason Kapono and Hedo Turkoglu were train wrecks.
Landry Fields got far too much money, though 60% of that signing, and the overpay, was an attempt to get Steve Nash to Toronto.
Give Colangelo a D+ for free agency, again, remembering most teams have to overpay.
So, that's a B+ drafting (most important), D+ (2nd round drafting, not overly important), C- (trades, pretty important), D+ (free agency, pretty important).
Overall a C- or so with generally strong moves lately, Fields aside.
Is someone better just lurking out there, ready to be snapped up? I doubt it.
* All this said. If Colangelo refuses to recognize that Bargnani doesn't fit with Dwane Casey's style or with a style that wins basketball games (gives up too much by playing horrible team defence and absent rebounding to make up for good offensive nights), then I can't defend keeping him. You can only throw stuff at a wall for so long before figuring out that it isn't working and isn't going to.
He needs to cut the cord, assuming there is a decent offer out there. Only then can the franchise really step forward.