[Poruku]

Sure you can gain a momentum advantage but you have to do that without hitting their back. Since you can't obscure, get in their back, and attack, unless you rough tumble but that only gives you one attack. So at best you're doing 2 actions from the front (better hope they have no riposte and they can't parry) then removing watchful eye and hoping this momentum exchange wins you the matchup. A bit of a weird dynamic imo.

And the main issue is for builds that NEED to hit the back because they are using a weapon that can be parried and riposted. So for Kensei/VA they are fucked regardless against a BK using this.

Also Hikage/Tsukikage already completely bypass watchful eye because the guy doing the watching turns to the position you were at previously, funnily enough still getting hit in the back. So those don't enter the equation.