Firefox is completely bloated. There is no unified way to do things, for example there are like three places where you can add the currently visited site as a bookmark.
This is no needed, any I guess most users can live with just using the icon in the adress bar.
There is a Project called SimpleMenuWizard which includes lots of UserChrome.css enabling you to make Firefox less cluttered.
Normal users have to be able to use this simpler menu feature easily, not more hard. There should be checks where you can enable "I am a developer, I actually want to inspect sites". Who does that? I guess 90% of users dont, also there are many many different ways to access this feature.
Inspecting usability and barrier-free-ness is also not a default thing, as well as sending things per mail.
Also things like copy, paste, select all could be left out, as there are well known shortcuts everyone knows.
This is such a powerful feature but its incredibly hard to use. And that its so hard is so absurd if you goal is to make firefox more userfriendly, especially for beginners.
Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.