What was unstable that you wanted to use?
(Not trying to deny your experience: reporting this helps the Rust team determine what to prioritize)
I think the nature of the 1.0 release and the train model is not very easy to communicate: the Rust team hopes to commit strongly to semver, so "stable Rust" is only that which they are comfortable committing to providing backwards compatibility for indefinitely. It's really pretty fine to be on the nightly track if you don't mind occasionally having to change a method call or something when an unstable API you use change.
Not trying to dismiss what you've said - I just think that the strength with which you expressed it ("Rust is still barely usable") was not accurate & that if you ask in the IRC channel or users.rust-lang.org, there is likely a no-or-little-hassle workaround for whatever feature you wanted.