I'd say 50-74%. It definitely isn't a bad spec, the core is actually really solid, it just suffers from minor issues.
This seems to be a reoccuring theme for a lot of specs in Legion though, and I'm fairly certain it's indicative of design in general. It isn't as though the developers hate Warriors or Rogues or any other class, they are simply focused on making the specs "good enough", rather than completely polished. Anyone who has ever been involved in any kind of time-sensitive project knows that you can't tweak forever, even if you want to. Eventually you have to call it done and move on, lest you run out of time for future considerations.
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I honestly wouldn't mind the Vrykul theme if they used it in conjunction with player race Warriors and it wasn't also a dungeon.
No matter how you look at it, letting other classes experience the area only detracts from it's unique nature. Allowing them, and even worse letting us beat up the "heroes" of our class hall, and gain Odyn's blessing, only further undermines our relationship with them.