I think about:config is terrible. It's really hard to find anything in it. It's very "if you know its there you will use" but has no discoverability.

For instance I was wondering if I could have one tab connect over a VPN while the rest were over my normal connection. I have no idea if that's an options somewhere in the millions of toggles

EDIT: You know how applications used to be have an "Advanced" button that'd give you a nicely organized display off all the "extra" toggles? Whatever happened to that paradigm?