There's ZERO reason for such an awful change to ever make it into a build, even the roughest alpha build. It's an obviously terrible change on paper, and that fact is obvious to everyone who has experience playing Subtlety. There is no reason to even entertain such an awful idea for more than a few seconds, let alone to actually get it into a build for testing.
I'm reminded of our gold traits in Legion, like Shadow Nova that breaks Saps or the original version of Akaari's Soul that ruined PvP openers. These issues were OBVIOUS on paper, within 2 seconds of reading the trait on paper you were shaking your head and saying "they really have someone running this show that doesn't have the slightest amount of experience actually playing that spec".