Cool idea! The problem certainly is real. I've manipulated the front-ends of some common websites through a combination of adblockers and userScripts to a degree that the site is almost unrecognisable when opened in another browser. But this takes time and can be annoying to maintain, e.g. if an element name changes in the HTML it reappears.

So I think your idea is great - essentially alternative front ends on demand!

The first concern is privacy - if I used this would I have to trust some remote server with my most private data (i.e. auth tokens)? It wouldn't be a deal breaker but I guess I personally wouldn't use it on, say, a banking website or gmail.

I also wonder about distribution. If there was an incredibly quick way to switch between commonly requested front-ends via 1-2 clicks (or keyboard shortcut), that would be awesome. E.g. you could analyse the modifications users ask for, sensibly add them into a single prompt, and build that front-end.

E.g. say users on youtube constantly request removal of the 'Explore more topics' section, pay per view sections, games content etc, then perhaps that collection of preferences could be made into a front end that can be accessed in one click from the extension (or keyboard shortcut). Perhaps allow the top-three most popular front-ends for that site just a click away. That way, a user of a website can build their own custom front end if they want (which can take a lot of work), but they don't have to if others have already requested it dozens of times.