Hi, there is currently a case against Firefox discussed in FESCo: https://fedorahosted.org/fesco/ticket/1518
The problem in short: The last release of Firefox doesn't allow the user to install add-ons which are not signed by Mozilla by default, in the next version, you won't even be able to disable this behavior. This means that a couple of add-ons that are packaged by Fedora won't work.
In my opinion, this problem has an impact on a relatively small number of users while suggested solutions will have an impact on majority of Workstation users. The author of the original ticket recommends Firefox is removed altogether if Mozilla doesn't change their plan, another suggestion is to switch to ESR which would mean that Fedora would have as conservative approach to Firefox updates as RHEL.
Firefox is probably the most important desktop app in Fedora, so I wonder whether the Workstation working group should voice its opinion in this before any decision is made.
Jiri