All extensions disabled due to expiration of intermediate signing cert

I never liked change that extensions had to be signed by mozilla.

Why do my personal extensions need to be hooked into some third party service that can go out at anytime?

The developer edition allows that just fine.

Developer edition is effectively aurora/alpha. It is buggy compared to release. And yes, I do mean that. If it were not it'd be 'release'.

Asking people to either give up control of their software (ie, walled garden release versions) or use buggy and insecure software Dev/Nightly/etc is not acceptable.

It's why I switched to a freedom respecting Firefox fork as soon as they announced walled garden extension signing in Firefox 37.

Sure: debranded versions ("freedom respecting") will also do that.

You say walled garden, I see what random WebExtensions people install on their work laptops and think "yeah maybe someone policing this thing isn't the worst thing". But most importantly: it sounds like it's not actually a problem for you?