The current mutability system is certainly reasonable. I think it's a lot more reasonable than one where there's a useless `&exclusive` / `&uniq` type that's not intended to be used. That's certainly a lot more confusing *to me*.

Beyond there being people who understand Rust and those who don't, I'm missing where there's any difference / vagueness in the understanding of the system. It's pretty clearly defined and well understood, unlike the borrow checker rules which are far more subtle.