If I were to decide how to nerf/tweek/balance Black Prior, first thing I'd do is make his shield bash punishable by guard break if dodged. Then I'd swap the damage of his light opener and light finisher so a successful shield bash will net him 15 damage, and a light attack from neutral will deal 20 damage.

Coupled with big fixes that'd be it

I have to commend Ubi for their handling of BP, he's pretty close to being a very well rounded character who is easy to understand yet still formidable. His kit is a bit too simple and lackluster in my opinion, but it works well enough without launching him into SS+ tier