Vulpera are coming.
It's now the worst kept secret in WoW, after the previous worst kept secret (playable Kul Tirans) was revealed last week. There is absolutely no way Blizzard would put that much work into the Vulpera if they weren't going to be made playable. Frankly I am a little surprised, I thought they'd wait until the Goblins got their rig update before going ahead with it (seeing as the share the same skeleton and all) but I guess that is for Blizzard to worry about.
In a world with Panda people, cute gnomes, cow people, hyena people, walrus people, snake people and even the Worgen, the Vulpera do not exactly stand out. Anthropomorphised animal races have a long tradition in WoW. What I believe is really triggering some people is that the Vulpera are cute, and the addition of a cute race really sticks in the craw.
As someone who believes variety is a great thing (but not duplication), Vulpera will appeal to players...and they do exist...who like cute thing and like playing cute races. There is absolutely no reason why they the Vulpera shouldn't be added to the game. If Vulpera aren't your cup of tea, there are plenty of edgy races for you to place. Forsaken, Void Elves, Worgen etc.
Now, in some ways the OP is distracting people from the true argument regarding Vulpera. Whether they will be Alliance or Horde. THAT is what will set off a firestorm in the forums once it is revealed because I believe the desire for Vulpera massively outweighs the antipathy of those opposed.
Circumstantial evidence, the presence of the Vulpera on the Horde continent, the fact the Horde will be the first to interact with them and (I think) that the Vulpera files share the same coding with Nightborne and Highmountain Tauren does suggest the Vulpera are intended to join the Horde. If that were to happen, it will feed into the huge debate that is being had where some Alliance players feel the Horde is getting all the good things. It will be interesting to see where this goes.