Honestly all I want from Firefox is better stability and performance - I don't care about almost anything else barring security. Firefox has become so unstable and slow (on OSX at least) that many people I know - myself included have switched to chromium. We don't want to use it but we have to because of all the crashes and massive slowdowns during long running sessions or when many tabs are open. This goes for stable, dev edition and nightly. It really saddens me and I'm sure others because of the great work that Mozilla does especially with regards to transparency, privacy and security.

Edit: I'm also in two minds about the plugin systems between the two browsers. The idea of all JavaScript plugins scares me to death, there really are no good download managers for chromium / chrome, on the other hand Firefox plugins I rely on like Evernote web clipper keep breaking and don't even work on dev/nightly when enforcing the new plugin system.

Big fan of mozilla and firefox. I've been defending it for years, but now I'm having a hard time. It's slower in almost any case than the competition, from initial rendering to switching tabs. Some stuff hang the page completly. Watching too many videos or scrolling too much twitter slow down the browser to a crawl even after closing all tabs and require a restart.

I'm not using firefox out of sheer ideology and support for the FOSS community, but it's not the superior product I used to sell to everybody.

Some are just starting to land after literally years of work:

You might be more interested in reading about platform improvements like getting Servo/Rust components into Gecko: https://blog.servo.org/2016/05/09/twis-62/

Or progress in multi-process support (codename e10s): http://arewee10syet.com/

While these are focused on Firefox to improve performance, stability and responsiveness, there are also experiments like the Positron project, which is making Gecko able to host Electron applications: https://github.com/mozilla/positron