Have you tried Vim Vixen?
I don't know where this was when I was searching for alternatives to vimperator, but thanks so much for mentioning vim-vixen. It seems like it's just a port of the parts of vimperator that still work with WebExtensions but it's so much better than the alternatives out there at the moment.
Now I'm migrating to using Qutebrowser, as it's the closest to providing a similar experience.