Prequel = protoforms= no alternate modes that are real life cars= GM cant sell cars cause of it = hasbro doesnt make as much money= bla bla As cool as a prequel would be, i just dont think it can happen because no brands would make money from it. Unless like pepsi can put billboards on cybertron?
The prequel problem is budget. No way you could keep the exact same number of parts with the same shading and other fine details at the current level without a budget that anyone at Paramount could accept. If it's on Cybertron you've also got no human stars and if Paramount is going to pony up a big summer action movie budget they are going to want some human actors in the movie.