I still think it was a mistake for Firefox to dump its old plugin model. The customisation was a USP for Firefox and many useful tweaks and minor features have never been replaced.

Today the ability to run proper content blockers is still a selling point for Firefox but obviously wouldn't be if they started to meddle with that as well. (Has there ever been a more obvious case of anticompetitive behaviour than the biggest browser nerfing ad blocking because it's owned by one of the biggest ad companies?)

Other than customisation the only real advantage I see for Firefox today is the privacy angle. But again that would obviously be compromised if they started breaking tools like content blockers that help to provide that protection.

It made me stop using FF on android.