There is clear BW favoritism with the imps.
Not only in looks (better fleet, better end game armor, etc)
But also in abilities and performance for the so called "mirror" classes.
Want proof? Just look at the population imbalance. It's obvious as ProfessorWalsh said that the imperial side was worked on first and then they just threw some crap together for republic. People care about aesthetics, and it's obvious how horribly the job was done for the republic.
Have you seen the republic endgame armor? Sentinel looks like a golden space samurai.