What you are saying is mostly true. These threads are mainly for people who request or fulfill.
(Or for people who like to abuse the whole request system, but that is a different thing.)
Splitting it would be a pain for sure, and not just the splitting is the problem but after that to enforce the rule.
Question is would it worth it, would it change anything?
I can see a thread like Backroom Casting Couch could be more viewable for users without the request posts. Is splitting the good way or should we just clear the old request posts more frequently?
But I don't think it would really change anything with the recurbate or the camwhores threads. I don't feel like people want to click on random links through pages and pages and pages.
I think people mainly find those fulfilled video request via searching the models name or when someone posts that link into the model's thread.
Fortunately some uploaders are adding those names into their links, so it is searchable this way.
But I definetly think the premium request section needs some touches, but it is hard to agree on things and see what would be actually useful.