I doubt that there's going to be much effort into improving the HTML based browser that they're using as a shell to the engine outside of making sure you can go to a specific URL. Things like hotkeys and autocomplete are nice, but not really necessary for developing on Servo. I could be wrong on that though
The browser.html team works on the frontend, so they are very much interested in improving this. You're right that Servo devs themselves often use an even more stripped down test harness that you supply URLs to on the commandline, but that may change now that browser.html has gotten quite nice :)
Well that's exactly the point (concerning autocomplete anyway). It would be nice to have if it worked... but right now it just gets in the way. And it's not even that relevant to the underlying engine, right?
