>If Pi-Hole had a webpage where you could put in a domain, i.e. cnbc.com, and it went off and loaded the html of that page, worked out all the other domains that html connects to, and then gives you a 'unblock' button to click, that would improve usability significantly, as even a non-techie user could use it.

It kind of already has this. Just tail the log in the web admin, then hit the site in your browser. Unblock the sites that were blocked on that request.

I've been using pihole for a year and have only had one site that refused to load. Was pretty easy to figure out which request it was and whitelist it.