For extra security firefox can add features like private dns as in chrome, it may help users to find their result more easy and filter malware or adult content if any kid is browsing by using their private dns such as 126.96.36.199 or open dns family safe dns. Same work safe search would do to filter out the mature content.
In regards to add-ons,firefox can add the add-on store as like in desktop version of firefox so that users may be able to attach some of their favourite add-ons, it may result in more seamless connectivity between to other devices operating firefox
Atlast, I guess most of the people agrees on this that firefox needs a ui makeover to make it more attractive instead of being plane with some wallpapers and shortcuts along with pocket stories. The devs can make it more interactive and pleasing to eyes like as example allowing users to choose wide range of wallpapers, somewhat bigger and easy to view shortcuts with respective website icon, news stories to fil the homepage and look more pleasing.
II hope future updates would include this features.