With stacked navigation allowing lots of open tabs, I hope we can also have efficient maintenance of those tabs. I don't need them to keep running javascript in the background. My machine shouldn't sag under the weight of a few hundred open tabs. After they've been inactive for a while, archive their state to disk and replace the view with a screenshot. Pull everything back into ram when I go back to the tab. If I take a second or two to look at the page before I try to interact with it, I won't notice a difference.

Let me whitelist a few exceptions, like gmail.

Built-in buttons to save/bookmark all open tabs would be nice too. And when saving a page, if there's a page title use that as the filename.

Optional feature: insert a meta tag to the html that gives the url of the page, so when I mention it online I can dig up a link to it, without having to bookmark in addition to saving.

Also I'd like a complete implementation of Vim and a pony.