Fair point. But the current situation of Mastery being the worst stat by a mile isn't a good option either.
Blizzard went through the trouble of redesigning MW mastery but fucked up the implementation so badly that it's universally avoided... again. That's a huge failure on their part.
I'd rather the unique spec specific stat be OP rather than underpowered simply because it's more interesting than crit/vers. That might be just me though.