I agree with that. I can understand that they want you to play as antagonist, but not everyone like this playstyle. I have talked with lot of ppl that come from coop games, most of them like the antagonist feature, but they like to play as raider. They don't like playing as antagonist.
I would suggest to add an option to get the weapon/whatever with raider rank too, even if it is a much higher rank. Star wars style, dark force is faster to get things, but you can get it playing the light side in the long run.
Antagonist can be a really frustrating mode for ppl that don't like pvp. If they can't win a match in 3 or 4 trys I think some ppl could leave the game for good if they can't progress in any way.