It's not as bad as you think, but it's def a sticking point. Persona tried to fix this, things like 5A and 5AA being things, 2Bs being universal AAs, C normals tending to serve similar functions, mapping certain functions the way they did, having SB moves that are intended as extensions, etc.
The main thing in GG isn't the buttons functions as much as it is the wonky ass animations and hitboxes, at least to me. There's a lot of times you hit a button and go "what is that supposed to even do?" when you first pick up a char. Every time I bring GG to newer players they have such a hard time figuring out buttons and how they're supposed to use them and I'm sitting here like :T the entire time.
I personally thin kit's worse in Blazblue to the extent of specific non universal esque tools and having to spend time with a character, but they laid out a lot of basic stuff to compensate, like the actual button layout and how things chain and can be taken apart.