That can just be attributed to budget though anyway. Rather than spend several thousand more dollars on making five different pre-earth versions of all the Autobots they just took the cheapier way out. Not that that's a bad thing, but from comics, etc. you can clearly tell that everybody's protoform mode is NOT the same in canon. DN
"Protoforms in this continuity are more than just the first stage of a Transformer's life, they are the "base" form that exists down inside each robot. Protoforms are made of an ultra-dense liquid metal material and are extremely hard to damage. In the rare case they are not actively practicing their natural proclivity for chameleon-like disguise (usually only when engaged in interstellar travel) Transformers shed their exo-structure and return to their protoform state. This protoform is capable of transforming into its transition form; an armored cometary shape capable of interstellar travel. Upon landing on a new world and transforming back into a protoform the Transformer immediately begins trans-scanning for new alternate forms to adopt. When one is chosen the protoform draws on its own ultra dense substance and any extranious matter nearby to generate a new exostructure disguise. " From here. So basically, a protoform is not the same as a Cybertronian form, but rather an inner "skeleton" used for interstellar travel. A lot of people have been making that mistake. The use of the term "protoform" on the movie preview toys (Optimus and Starscream) is probably the biggest cause of this misunderstanding. While the protoforms may be identical, back on Cybertron the Autobots and Decepticons would have looked like themselves, with Megatron being one of the few transformers of either faction who can engage in spaceflight without reverting to a protoform.
