While KS is great and very fast, there are a lot of things I love in C4D and I think it would be cool to be able to use KS inside C4D, you already have the materials and tools imagine what the combination of both would be :)
There's a live link plug-in that allows you to link your C4D file with KS. As for KS functioning as plug-in inside of C4D, I wouldn't count on that happening.
As an avid C4d user, yes this would be awesome. I've asked about it before with crickets in response. So, yeah probably aint going to happen. I know for Octane it took an independant developer to create a wrapper for the main Octane app for it to be used in Cinema. It worked, but kludgy and there were always things that didn't work. So, I switched from Octane to Keyshot. For the work I do now, I can assemble most of my scenes in KS and use Cinema for geometry work or fixing stuff. I miss playing around with x-particles though. would be awesome if X-particles made a plug in for keyshot.
totally wonder what the plugin page in the KS preferences is for, doesn't seem to be anything that ever goes there?