Filling in the Plot Holes
Ok a Major Complaint i hear is that The plot didn't make sense, but it actually did if u pay attention
A major Plot hole i hear is "Why didn't Sam use the all Spark shard on Optimus instead of Jetfire"
the Whole reason they went looking for jet fire cause he was the only person who could read the symbols, Their Revelation that they could bring prime back was after Jetfire Explained every thing
Also Jetfire was'nt dead; the shard did'nt bring him back to life. It just woke him up. I could be wrong but I think Sam still had the Allspark piece anyway even after using it.
Jetfire had just been hiding out on Earth from the war and had somehow settled into an airplane form.
Sam also might not have known that Megatron was revived by a shard of the Allspark, since no-one told him the Deepticons stole it. He probably had no idea how he came back to life. And Megatron's injuries were not as serious as Optimus's, so the shard might not have worked anyway. Optimus had his chest ripped open- Megatron just seemed to suffer a heart attack or something.
Anyway, main point is- Jetfire was'nt dead.
Also, to revive Megatron the Decepticons killed one of their own and used his parts for repairs- the Allsparks was'nt enough. The Autobots are'nt likely to do that.