Ignoring the fact that I pulled those race-class combos out of my ass for the sake of example, why would they feel wrong? Look at the different races/nationalities of real life humans on Earth and compare that diversity to the different "races" of WildStar. Just because someone is american, it doesn't mean that they can't learn and master various eastern martial arts practices. The idea is similar with universal classes. I can actually totally picture a particularly aggressive and/or spunky aurin going out and training with a sword so that they can come back to Arboria some day and kick those Dominion punks off their planet. Likewise, I could see an especially erudite granok being drawn to the mental discipline required to become a skilled esper. Obviously, these kinds of things would go against the "stereotype" of the species, but wouldn't that just make things more interesting? NPCs could react accordingly. Roleplay is enriched with deeper characters that don't rely overly much on racial stereotyping. All in all, eliminating race-class restriction becomes a boon to the universe's storytelling, not a hindrance.