Personally I think it would be even more interesting (idea is good, so props for it) if there were two group of players. Those who want to create rebellion and free the world and those who actually are part of those big bad corporations (for example Hasbro idea with deranged brony controlling pony mecha is so hilarious and dumb at the same time :D). It would allow to show world in more detail from both sides. At least this is my opinion on this.

And I assume that countries don't exactly exist anymore and all lands are part of corporations ? Also when you mentioned aliens - is it just limited to earth or actually some action could happen on let's say Mars or Moon ?