Honestly I quite enjoy writing character sheets (even though I put it off all the time) since then I can reuse the characters elsewhere if the rp doesn't work out.
Well, I only really got into writing after I read some books by Brandon Sanderson. His prose is kind of plain, but his skill with worldbuilding and creating magic systems is unmatched, and that's what I draw from when I write. My writing style is also somewhat influnced by Brandon's own...
I mean, if it's good stuff that makes for good ideas, than I wouldn't stop doing it.
It's not always media either, like I try to follow Sanderson's Laws of Magic whenever I do worldbuilding, since they definitely make for good stories.
The Wheel of Time is a great setting for a roleplay, since the worldbuilding is so in depth that you could do a story that has nothing to do with any canon characters. The same is true for Brandon Sanderson's books, in particular the Cosmere, but I'd love to do a Skyward rp as well.