> What are possible alternative mappings to make it more intuitive to non-developers?

Arrows.

But for the other camp - the Emacs people - n and p would be best :).

May I suggest adding an options page to configure the keybindings (and store them in browser.storage.sync)? Happy to send a PR.

Sure, let's discuss this on a GitHub issue first :)

Will fork for w,a,s,d support :P