Without REX I can’t really use it. Adding support is pretty simple; the SDK has been well maintained.
Recycle was one of the first apps/plugins to handle loops and slicing. It was quite advanced at the time. Nowadays most DAWs, if not all, are capable of what it’s doing now. Even CR8 which offers you a few different types of looping algorithms.
I’m just not sure whether any developer would go to the extent to support it when you can use any audio file now. Especially if there is a licensing fee involved. Even Propellerhead is giving it away these days, albeit with a few convenient updates.
But who knows, maybe its popularity will boom again and Waves jumps at the opportunity. Never say never.