Fair question. While this applies to other characters, they also have things to make up for it. For example, Litchi has an excellent neutral game, and even if you can block her, she can force you to block. If you don't block her overhead 10% of the time, it's easier for her to get those 10 chances to make you have to block it. I'd argue that the characters that this most applies to are the ones that are regarded as bad (Makoto, Tsubaki). In EX, Ragna makes up for this by punishing you heavily for the (what should be rare) time that you mess up. In CP, he losses this.
Oh, and i don't know who's idea it was to make neither version of Blood Scythe an overhead, but lol.