Agreed. It leaves you really open. I didn't feel like it was that unfair either. I felt like it was a perfectly viable baiting mechanic. On top of that, you can't parry for a solid like half a second after the power slash goes off, so you can't even cancel, then parry which is how most abilities...
I've gotten stuck in walls multiple times on Yamato now. The unstick hero command doesn't work for it. it seems to happen when using grapple. ( i think when you slash at the end of the grapple is when it happens)