The eternal struggle of the TF universe, to me, has always been about Optimus vs. Megatron. The two characters epitomize opposing ideologies. I'm not saying this just because I'd like to see the movieverse continuity continue as already established in future films, although I certainly would. I hope Megatron escapes earth, avoiding death and keeping the possibility of returning someday with a rebuilt, repaired, powerful body alive. Imagine the power of a future showdown between he and Optimus given the long history built between them in the course of three movies.