I apologize if this idea has been suggested before. But after playing Dynasty Warriors: Gundam with a friend, I have to admit I like the whole concept. Take various heores from all the ages and realities of Gundam, stick 'em together in mixed teams, and let them go at each other on the Dynasty Warriors battleground. It works for Gundam... especially as they took the time to develop interesting interplay between characters from different series. Who would have thought that Domon, Milliardo and Puru would be a fun combo? So... why not Transformers? Grab characters from G1 through Cybertron, cherry picking the favourites from each. G1 Optimus and Megatron, G2 Jihaxus, Armada Starscream, Beast Wars Optimal Optimus, Cybertron Hot Shot, Classics/Stormbringer Jetfire, etc. Put them in unlikely alliances. Toss in a huge number of grunts (Seekers, Terrorcons, Scrapmetals, Shockwave's Drones, Sweeps, etc) and have them fight their way through. I think, if done right, it could work really well.