Who says Neverwinter and user created content are synonymous? Neverwinter is just a town, just like Baulder's Gate. They are settings and places to tell a story from, that's all. And the only "hardcore" fans I've found that don't love this game are the ones who are still stuck in 2nd edition and can't move on with their…
They just started out with the 4 iconic core classes for launch. Ranger, Bard, Druid, Paladin, Monk, Sorcerer are all bonus classes that are kind of off-shoots of those primary 4 but they will come :)
There actually is an official 4e Black Guard. It's powers similar to a Paladins, but kind of opposite. Where a Paladin might gain a bonus to hit based on how many things are around him the Black Guard got a bonus to damage. With how many classes are in 4e they have dozens of classes they could still add to the game.