The thing missing from both those implementations is link following. That's the "HT" in "HTML" and "HTTP", so no supporting it from the keyboard seems almost unacceptable to me in a web browser. Yes, I'm aware that no major brower _ever_ did support link hinting out of the box.

I'm using Tridactyl now, and am extremely happy with it. There are some problems, notably on the lack of Tridactyl support before the page loads, but with TreeStyleTabs it is the best browsing experience I ever rememeber having.

Imho, the right approach is the one taken by qutebrowser, a lot of shortcuts yes, but it's almost impossible to only use the keyboard and, when you do so, you can't be as productive as when you use the mouse, because it wasn't designed for a keyboard centric use.