Mozilla says[1] about the Developer Edition that it "replaces the old Aurora channel" (so it's like a rolling-release alpha version) and has "tools that aren't yet ready for production". I don't think advanced users should be expected to run an alpha-quality, experimental, non-production version as their day-to-day browser just to get their configurability back.

Setting the defaults to values that don't confuse mainstream users is fine. Removing the corresponding settings from the settings dialog or other easily-accessible UI ... maybe. But removing them even from "about:config"? That used to be the place explicitly for advanced settings for advanced users, settings that were too scary for the UI. These settings need to be somewhere. (What if mainstream users discover the Developer Edition? Mozilla will have to make a Secret Developer Edition to make sure only the real advanced users can find it!)

Also, where in that Bugzilla thread are bookmark descriptions mentioned as being an attack vector? I can't find anything about it.

[1] https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Dev...