The only thing that didn't make sense for me was this: okay, Optimus dies. No problem there. The Decepticons steal an all-spark shard that was under military lock & key, which is, you know, so far so good. They don't ever really acknowledge the shard that shakes loose from Shia's sweatshirt from the first movie at that point. Instead, it's like, oh let's take this shard to the Air & Space Museum and revive some old codger Decepticon Jetfire who doesn't really wanna be a Decepticon any more, instead of using it straight away to revive Optimus. That is the only thing that made no sense to me. You could argue they needed to revive the Jetfire to be told that the language/symbols in Sam's head are in the Prime language, but wouldn't the priority be to revive Optimus.. wouldn't a Prime be able to read/interpret the Prime language?