I find the groups rather random, but the same with other mental illness. It's like making cookies you cut out of a sheet of dough. In a way your cookie makes sense, but you always end up risking being between cookies or that your personal cookie has parts and not full parts of the cookies they decided are real.
The main issues I see with personality disorders is
1. The name. It implies who you are is disordered. If you are cured, you will also be someone else.
2. No cause is needed for a personality disorder. That groups people up with totally different backgrounds, it mixes people with brain dysfunction with people with bad childhoods. And claim that the effect is the same. I disagree. Even if nurture and nature cut into each other, cause must be considered.
3. Gender differences are too big between PD's. With the same behavior, a female can be diagnosed borderline or histrionic, while a male gets diagnosed ASPD.