Rebellion is kinda weak in some areas I must say. The concept is there, but things like the interface are quite lacking, not to mention some real battle tactics.
No I don't mean you have to do a nice battle lines like those boardgames even though that would be fun. Think star wars "xxyy front" ... or "hammer of the scorts"
OK, back to topic. Diplomacy is fun, but can take away from a story, think about those railroading a story-driven campaign would have. E@W is not that kind of game.
And rome total war? Well, I find the game kinda disappointing. I mean, most battles degenerates into groups of skirmishes fast, and my nice line is gone into chaos quick. Sure it is fun slaughtering my opponent, but the feel of combat is lacking for the era.
To be fair, I don't mind a Clone Wars era expansion at all. In fact it would be a great idea.
I mean, what we are playing in E@W is a big what-if anyways, so why not do it in the good old CIS conflict? And the plot of clone wars is not too bad really, including all the EU stuff. That, and a jedi on a lizard would be fun.