I want to see something like https://web.hypothes.is made native in browsers, so you can have community overlays on websites and commenting based on a group you subscribe to, automate common operations teams perform on web pages and leave notes for them etc. with out the websites itself being entirely in control of the entire ux and functionality.
We actually thought about adding a similar function in the beginning, but discarded it later since we wanted to focus on the existing key problems, rather than adding productivity features for power users.
Nevertheless it is an interesting topic worth exploring.
In the same vein it would be interesting to explore mechanisms of automatic discovery - e.g. proposing tabs that have close horizontal proximity in other people's collections. Sure, it opens up the questions of privacy and data collection, but it could provide a much needed alternative to using search engines for discovery.
I'd like that too. And perhaps the browser should know about the concept of "user-reviews" (where the reviews are customized per-user, i.e. computed based on the groups you are in, and who you trust, etc.) Thinking about it more, that's what the web needs most: reviews that we can actually trust.
