Letting Fisher go was a bad decision, IMO.
Laker fans have a tendency to underrate this little thing called chemistry, which is why this year's team was actually worse than last year's team. If they'd kept Kobe, Lamar, and Caron together for this year, this would've been a 50-win team, even with no talent coming off the bench.
I've never been a fan of Odom's game (because he's such a liability on defense) and never expected him to become a star, but he's a very serviceable NBA player and I like the guy. I haven't seen any flashes of brilliance from Bynum. Yes, he's 7 feet tall, but even though he gets a couple of blocks and grabs a few boards, I just don't think he has the raw tools to become the next dominant big man. Even if he does, he's at least 3-4 seasons away from being even a good big man.
Trading away Odom to get Garnett would leave the Lakers as a decent team with 2 superstars, meaning they'd still be 1 star short of contending in the West, especially if Utah holds that group together and improves. Even with KG, the Lakers would still be fighting for 3rd in the West beyond San Antonio, Phoenix, Dallas, and possibly Utah.