You can't say that the Magic failed their attempts at improving, although you need to look at a few very important variables that are affecting them.
1.) Stan Van Gundy is a decent coach, but he has lost his cool one too many times this season and it's likely that the core players are losing faith in him.
2.) It takes time for GOOD teams to gel with new players. Bad teams don't have much to lose, and you can see trades boost their abilities instantly.
3.) You have to recognize who the Magic have gotten rid of. Vince Carter, who is not able to perform anywhere near as consistent as J-Rich has at the respectable points in their careers. Gortat was HUGE for them, and that loss did set them back as far as the depth the Magic need to match up with the elite in the playoffs. But, guys like Dwight love the added weight on his shoulders and he's performing well in the role. That means the Magic identified chemistry problems with Gortat being a second fiddle, when he could start for many teams in the NBA. The Magic traded him for hopes to land someone who accepts the backup role. Will it happen? Maybe, maybe not, but Gortat's stock wasn't going to go up if they ignored the problem.
So really, the Magic were damned if they did anything, but that doesn't mean they are out of the picture. They just need time, and when you have once a decade Center like Dwight, you wont really be a bad team. They could easily bring back the same exact team next season and improve a great deal, just as long as the players are on-board with SVG or whatever coach.
Now, the Celtics... that's a different story. They basically said to themselves that they can't afford to keep this team together, and if they have opportunities to make a small, low impact move, that they were going to be open to it. When Ainge commented on re-signing Peirce in the offseason, he made it clear that it was due to loyalty more than business. This would lead me to believe that at some point, good players are going to be shed off the books. Why Perkins now, and not after the season? Nobody still knows, but the only reason why it makes sense, is the sense in Ainge's head.
That doesn't mean it was a failed move, but will it come to fruition by the time the Celtics need it the most this season? It very well could, and just like the Magic, the move might be too early to really tell.
Personally, I think Jeff Green is a good player, but for a PF, he has the same consistency as a bench shooting guard. You just never know if he's going to play to his potential.