One thing this blog post points out is Rust ecosystem docs. I've been trying to find a good way to evaluate this: https://users.rust-lang.org/t/lets-talk-about-ecosystem-docu...
Other thoughts:
Crates.io, our package server, uses Rust + Ember. One thing that is really interesting about Rust in this space is memory usage: last I heard, crates.io uses a flat ~30 MB of RAM, resident. I'm used to Rails where that is... very different.
On that note, I think "Rust serving JSON + Javascript for the frontend" is a really interesting stack. I've been trying to find the time (and hopefully roping another person or two in) to build a http://jsonapi.org/ library for this purpose. I have a project where I've been using it, but I went down the "why use a library, I can generate the JSON by hand" and it's.... ugly. Serde is so much nicer.
As always with a young ecosystem, we need more libraries. For everything. It's gotten a lot better, and much of the basics are there, but sometimes, you're still going to have to write things yourself, which slows things down.
mio is gaining preliminary Windows support, and once it does, hyper will roll it in, which should significantly improve performance in many web contexts, as well.
I largely come from Ruby, where Rails was such a leap forward that people learned Ruby just to use it. I expect that if you know Rust, writing application-tier Rust will be fine, but I'm not sure it will ever see the same kind of pattern.