Yeah, "they're optional", but so is every race except humans and orcs. You could even argue that most classes are optional. Yet all the other races are freely available and only the two hero classes have gates, one being a level 55 character to unlock dks (which has been removed) and now the dhs which require a level 70 character. But leveling is the bare minimum gameplay. Having races unlock after a months long rep grind that's locked behind a max level toon with friendly rep with four factions is fucking stupid.
I don't know if you were around when Belfs, Draenai, Worgen, Goblins, and Pandaren were released, but damn...those were some fucking grinds to unlock. I mean...oh, wait. No, there wasn't a grind.
That's my specific complaint. But it's a general problem with WoW and other MMOs.
Getting to play with the neat and interesting stuff shouldn't require a months long part-time job just to unlock. Yeah, it's a part of the genre, but it's a shitty part of the genre. I like playing WoW, especially the non-grindy bits; but the grinds are getting worse and worse, yet some fans are cheering this on. WTF?
In no other genre will you see fans say anything remotely like: "It's so boring." "I know, isn't it great!" Yet we get that all the time.