If you picked the Empire because you'd thought you'd win, you might want to go watch the original trilogy again. The situation before "A New Hope was the same as it is here:
The underdogs have been losing incredibly badly for the last 20+ years, but then a string of major victories in a few short years turn the tide (despite numerous setbacks) to set the Empire on the losing side, The Empire losing it's Emperor and most powerful figurehead (Vadar/Malgus) soon after.
So no, I really don't feel any sympathy for those suckers who went Empire and are now mad that their choices mean nothing.
I know the Empire is going to lose sometime in the next 3000 years
, if Bioware plans for the Republic to just win constantly right now
, they shouldn't have bothered making the Empire a playable faction.
"Oh well, in the background fluff that has nothing to do with you the Empire was totally kicking Republic butt, but in the game that you actually get to play and interact with, you're just here to lose constantly." is not a good business strategy.
I mean, you're clearly a fan of the Republic, if the Empire won every major victory and everything you did as a Republic player was irrelevant, would you really be content with, "Oh well, at least I know that in a few thousand years due to events that I don't see or have anything to do with we win eventually anyway." ?