Moving rawpedia to something managed via PRs is, in my opinion, an excellent idea.
I also agree with @Thanatomanic that this is one of the many reasons for creating a github organization for RT - to handle ancillary repositories. I think most of the RT team is fine with github, after all everyone has been working with @Morgan_Hardwood 's repo there. I know I’ve been meaning to submit a few documentation tweaks regarding color profiling to rawpedia but never got around to requesting an account, doing a github PR is far easier for me at least.
(My personal stance on github and microsoft is that while MS has some really egregious behaviors in their history, I’ll give a company the benefit of the doubt if executive management has been changed out - post-Nadella MS is a lot better behaved and even friendly to FOSS vs. pre-Nadella. So I’m happy using github, VSCode, and WSL. 
)