See the history as a tree, not as a list, so branch points can be preserved and you can navigate back over everywhere you've already been. A detailed development roadmap. Privileged browser Apps and Extensions working on mobile. C'mon, it's 2015! ( no PhoneGap required ) An automation API. The same really committed team who optimized V8. Source on GitHub ( not necessarily all of it mind, some can be privileged access…
A dev roadmap is just a general program requirement. Not specific to web browsers but good.
And you're right about mobile and extensions. There's no need to restrict when you don't have to! For a web browser on iOS, sadly you have to use Apple's engine but that's workable with js injection for extensions. And of course on Android there's no problem. I like that iOS is opening a little (I have an iPhone) but I wish it was more open like android, that way jail breaking would not be required for a lot of features. The one good thing now is that they're letting you side load apps from source with Xcode 7 without paying, but it's some michigas to go through. Mobile platforms are weird.