I've given it more thought.
We have to consider why the ship crashed in the first place. Was it shot down? Earth's Magnetic field? How come the crew of the ship didn't wake up before the humans touching it.
I'm ruling out Unicron as the moon thing, for one single reason. It's the moon, if it happens to be Unicron and he transforms, Earth is screwed, it would be the movie 2012 instead of Tf 3.
I like the idea that it is a prime. But I don't think they'd contradict themselves that he's the last prime , and build the entire second movie on that concept. So no prime.
So the guy is old, and he's colorful. His eyes aren't red. Meaning he's an Autobot. He has Cybertronian language on his crown.
Let's think as they do. Why would they show us this guy in the trailer. And not something else. His features are similar to all what you guys mentioned above. Primarily being Alpha Trion. I'd say 80% he's some one we know. Since the teasing is useless if it's a totally new character. It could be Sunstreaker for all we know, or even Huffer. They made Jetfire an old bot, why not someone else in a new light. Silverbolt?
But what does it mean that this guy is waking up? Usually in trailers like this, it's a foreshadowing, he's evil, he wakes up. But this guy is good (sort of). What would him waking up mean? That he is a messenger warning us of the impending doom ? (Unircon for example). Why would they tease us about someone waking up who will end up being good and friendly. It's definitely not the discovery by the human race. Because by now, I think the human race already knows.
I'm guessing it will be related to a revalation for the Transformers more than the humans. Maybe he knows who made the Allspark.
Autobots stink, they call themselves good, but are they?
Decepticons are the true saviours of our Cybertronian race