Weird issues with add-on are definitely a problem, and with poor performance, one of the reasons I switched to Chrome. But when it comes to JS, and I'm willing to bet my bias as a web developer and website owner influences this, I don't think this should be easy to change.

Maybe Firefox needs a better warning when someone goes into the config; it wouldn't be the first time. But JS is not only a part of the browser, it's a core part of the web, good and bad.

For this reason, I don't believe that it needs to continue to be easy for someone who doesn't understand that to switch it off because of false or misleading information. The web has grown since JS really started being used, and won't be going away anytime soon.

Most people turn off JS because of security, because loading a web page should not always lead to code (besides rendering) being run on your machine.

"Most people" don't turn it off, those who do are sophisticated users and can easily download and use NoScript (and probably already do), which is a far smarter solution allowing for you to use the modern web on sites you trust.