It's funny they want to rewrite some of the core functionality in Rust and make it available through an N-API binding. I've mentioned on HN (and gotten plenty of hate for it) that another approach to gain performance with Electron is to use a back-end language to serve up a local web page, I can only imagine just using a Rust or D web framework that can handle heavy data traffic, only running on 127.0.0.1 serving up some of the content the Editor (or whatever application) needs and doing some heavy lifting from Node itself. In fact I think there's already an open source mail client I don't remember the name that does this, it feeds Electron from a Python back-end, would not surprise me if they're doing pretty well performance wise, let back-end people do their thing, and let front-end people do theirs. Of course things will also get interesting whenever WebAssembly becomes another way to build an Electron application (really can't wait for WebAssembly to become totally mainstream). If my website had half of the stuff on the front-end that my back-end is supposed to handle yeah people would call me out for shoving so much into the DOM / front-end and suggest I offset some of the heavier stuff into the back-end.
Long before Electron I saw applications that ran on localhost in your own browser (think SlickBear, CouchPotato and Headphones) and they were highly responsive regardless of browser used! They were all coded in Python too, so I can only imagine if some of those native API's could just be done as a web api instead to keep things simpler, then you just need to identify a REST framework to handle some of those things. Anyone could add on to a RESTful API for the editor / call said API as well, though it should be locked down securely for obvious abuse reasons.
I used to like the idea of taking nw.js and making something like Atom (before it was even a thing) but using D as a back-end language for it, but never really got through doing it. Ah well.
Edit:
I also find it funny they're ditching CSS for JavaScript when Firefox redid their CSS engine in Rust. I have to wonder if and when Electron will deviate from Chrome altogether and become it's own forked browser engine, but maybe that's a thought a bit ahead of it's time.