Such a good idea. Do you have any plan to polish this up and publish to an extension store?
More the opposite because you have to totally trust the source.
Web stores search for certain malware patterns and get at leat some.
You gain no security from an unpacked extension.
Given that uBlock Origin can do this, I'd recommend that route. uBlock Origin is probably the most trustworthy extension I've ever run across, and Gorhill has proven that he is trustworthy over many years.