Why Transformers 2: Revenge of the Fallen?

It appears to have a pretty solid theory behind its meaning. Thanks to IGN we have the explanation

IGN.com says:

The site points out this entry on the Fallen, which reminds us that “the robot who would become the Fallen betrayed his creator by siding with Primus’s dark twin, the malevolent planet-eater, Unicron. In the final battle between Primus and Unicron, the Fallen fell victim to the same fate as his master, sucked through a black hole into another dimension. However, while Unicron emerged into another universe, the Fallen was not so fortunate, finding himself trapped in the ‘underspace’ between dimensions.”

I like that they are paying tribute to this little known ancient character from the G1 universe which clearly inspired the current movie incarnations.

According to the Transformers Wiki The Fallen was a servant of Unicron, which (if acurate) implies that they will talk about Unicron in the movie Universe. Involving some Unicron mythos might involve the theorized return of Megatron as Galvatron, an unwilling servant of Unicron - as illustrated in the Animated Movie.

So being that this is a movie adaptation they don’t strictly have to stay with the Fallen mythos. Perhaps Megatron returns as an amalgamation of this Fallen? The Fallen was shunted to some sub-parallel Universe, and perhaps through Megatron’s rebirth he is possessed by this ancient spark?

Maybe Megatron is going to be one of the original 12? Perhaps he IS the Fallen and in his rebirth becomes the dark loyal servant of Unicron.

And as suggested in previous comments, Unicron will then appear in the movie as a storm cloud.

So what do you think about digging up this ancient history of the Transformers Universe as the basis of the sequel’s plot?

Is Megatron the Fallen? Or are we about to meet a new threat?