A dismemberment takes time, and can also be driven by torture/murder being the point. For example, it's suggested that Peaches' cause of death WAS the dismemberment, the decapitation to be specific. Whereas the GB4 were strangled, a comparatively bloodless death.
The dismembered victims weren't mailed to anyone, no, but I think that's a relatively rare thing to happen, particularly in the modern age. It's not the nineteen twenties when you could ship a steamer trunk to a random address anymore. Hence a lot of dismembered victims ending up like Cherries, Evelyn Colon, and Aydil Barbosa Fontes - put in suitcases and thrown in waterways.
But a big upside of dismemberment doesn't exist any more. Hindering identification. With DNA, it doesn't matter how many parts someone is cut into, or how far you distribute them, DNA will assemble those parts into one person, and eventually, give LE a name for that person. So, for someone to cut someone up, they have to be determined. They have to be driven. Since identification isn't hindered by dismemberment any more, the two things remaining are transportation and gratification. Transportation for RH? No worries. He's a big strong guy with a car designed to transport a body (okay, not specifically designed, but very fit for purpose.) So, we're left with gratification. The kind of person who cuts somebody to pieces, alive or dead, because it fulfills something in them.
Whether RH and the killer of the dismemberment victims is the same person? I'm undecided at this point. I don't think they're as different as they appear on the surface. I think it's entirely possible for someone to start out dismembering to hinder identification, but then move to disposing of victims intact once it becomes clear that the advancement of DNA science means it isn't worth it. It wouldn't be satisfying for someone who just wants to dismember someone, or be practical for someone who needs to dispose of someone in smaller pieces, but it would be fine for someone who primarily cut bodies up to try to outwit LE. And, as someone else raised a while ago, if we leave out Cherries, then there's a progression from Karen, Peaches, Valerie and Jessica, all dismembered and scattered, to Asian Doe and the GB4, none of whom were, and all of whom were deposited on the same very small section of coastline.
Whether RH is responsible for the dismemberment victims or not, I think he has a body count stretching back far, far further than the GB4, so if we should be looking elsewhere for those victims, then where? I guess that's what we're going to find out as this case progresses.
(Oh wow, this was very long, sorry folks, apparently I have ~*ThoughtsTM*~ about dismemberment.)
MOO