I want to add my personal bugbear, sortable and filterable tables. And Lists of all links on a page. Oh, also expose RSS feeds again. And what about standard form controls that actually could be styled completely with css? Really, the more I think about it, the more come to mind.
While it sounds like it would make browsers more complex, I think it would actually reduce complexity, because the browser would not need even more programming capability and APIs just to enable web developers to create these kind of features themselves in a thousand variations of Javascript that adds bloat to every connection and slows down end user devices.
I agree with these things. I forgot about sortable and filterable tables, but it is correct it should be having. (I would also like the ability to override the browser's default styles without overriding those of the web page, in addition to the ability to override the styles specified in the web page.) If the browser uses SQLite databases for anything (such as bookmarks and cookies), let the user enter SQL commands to sort/filter HTML tables (and export them too, since the commands are entered by the user rather than the web page author, they are privileged).
And, yes, it would reduce complexity in the ways you specified, in addition to improving efficiency and allowing the user more control, and these are good things to have.
Maybe someone will make a web browser program that can do these kind of things.
While it sounds like it would make browsers more complex, I think it would actually reduce complexity, because the browser would not need even more programming capability and APIs just to enable web developers to create these kind of features themselves in a thousand variations of Javascript that adds bloat to every connection and slows down end user devices.