I'm a little bummed. I feel like it was just a little bit ahead of it's time; JS resource usage is just too great for a mobile platform - especially targeting the low end (Chrome OS showed it works - nicely even - on desktop). But with wasm on the horizon, will that be a problem much longer? And offline-first progressive web apps are quickly becoming more and more viable with the latest web technologies (service workers, web workers, indexeddb).
But with cutting this and Thunderbird, hopefully they can focus more fully on the browser, and moving Rust & Servo forward quickly (Edit: woohoo!), and maybe make up some ground/users back from Chrome. I think a renewed focus on privacy and identity in the browser would be huge. About a year ago there were rumors that FF might bundle Tor for private mode; maybe that could come back. And maybe they could bring active development back to Persona.
With the new (Chrome- and Opera-compatible) extension API, separate processes per tab, and the browser chrome soon apparently being handled in html/css/js, there are reasons to excited for FF's future.
That's disappointing. I had hoped Mozilla would be able to give us reasonably private and trustworthy mobile devices.