rustc (via Ferrocene) is already being qualified, and form what I hear it’s been fairly easy to do so, for various reasons.

Yeah it is and that's a great effort, I've worked with that team on various things. But the industry is still itching for a second compiler with no crossover (can't just be another LLVM frontend or rustc fork) for those certification reasons. Not that people want to replace rustc! It's just a cert requirement.

Yeah certainly wouldn't hurt :)