I think the main lesson is that bookmarks don't work too well or people just don't use them. If nothing else, make the bookmark display show newer bookmarks rather than the same old ones from four years ago. And maybe start preloading if they are opened regularly. Merge two features together, maybe add optional other organizational features for example similar to new tab screen.
The tricky thing is that there are a lot of things that are potentially supposed to happen while a tab is open. The browser is now it's own OS, and it may be very difficult for developers to use important features if tabs (processes) only _look_ like they are running.