There are a few Microsoft employees already working on improving Electron. Notably helping keep it up-to-date with Chromium [1] (current release at v61—6 versions behind stable).
Security is an area that could use a lot of improvements. Along with keeping Chromium up-to-date, sandboxing still needs more work [2].
Personally, I'd like to see greater support for Chrome Extensions instead of Electron's preload scripts. They're much more powerful in terms of controlling when scripts are run.