Elm’s approach and target is just different from Rust. Rust aims to be a good language that the community loves, while Elm’s priority is not to please the community, but the consistency of the language and enterprise adoption afaik.
Evan specifically wanted a different kind of open-source community for Elm: The Hard Parts of Open Source and the path is more relationship and trust based unlike other open source communities that encourages a flat structure: What is “constructive” input?, where he emphasizes “All of us make choices like this because we have a personal relationship to the work and each other that makes it worthwhile.”
Guides and docs are crucial for early adopter’s experience and hence any change I think requires Evan or any of the core member’s trust, instead of long blog posts/comments/pull requests with reasoning that would waste their time.
For the improvement of Elm Evan has a list of encouraged tasks to contribute that fit into his mental plan of Elm: Elm Projects.
Other than that, according to Evan’s recent tweet, you can make something in Elm, especially big projects, and write a report on why Elm is good choice for this. https://twitter.com/czaplic/status/1097966421009752070
I tried to use Elm for prototyping small web projects and found a lot of obstacles in the learning process due to the uniqueness of the Elm community. But compared to other competetors (ReasonML/Purescript) the Elm community is much better. Rust is a good choice but it is not there yet for front end.