Long story short: every single race should be able to choose and pick whatever class they want to play.
It seems that developers are too afraid to challenge and experiment with some of these foundations that almost doesn't mean anything in reality. Finding the ways and then allowing players to pick a class and their favorite race, and combine them together, would be an ideal and satisfactory outcome. Some of these magical inventions should take place now, without any fear.
I'm not invested in WoW, nor I play this game, posting out of nostalgia believing that the ancient and almost religious stubbornness isn't a right way to go. And with a upcoming cross-faction, the all-time sworn enemies Horde and Alliance are coming to play together for the rest of the time. It only a proves that they can do more with breaking up those ancient chains. The old men and women who wrote Warcraft aren't any fabric of any reality, everything can (and should) change in favor of a better future.