The Republic faction is just so much more un-attractive compared to the Imperials.
Story lines, cosmetics, atmosphere,etc, etc.
Very poorly designed, the developers should have known they needed more "cool" things for Reb's because of the fore-knowledge that most would play Imps.
Not much they can do now. They've made their bed now they have to sleep in it....well, at least half of it...
What we're they thinking?
What foreknowledge? I personally expected Republic to be more heavily populated, myself.