[sounds]

But why make it easier for the site to track you?

Force them to do detailed packet timing and their costs will go up, and it will become less economical for black hats to play around with your personal data.

I don't know if nuking the user agent string is a horrible idea, but it's less of a problem today than it was 5 years ago: today, a website can assume all browsers conform pretty closely to a standard. Only really advanced features require user agent sniffing (arguably, if you're sniffing the UA you're doing it wrong).

I think we should make that kind of fingerprinting opt-in, not opt-out.

[guessWhy]

I think changing the user agent to only report the major version would already go a long way.