@tonzeli They recently fixed a bug where AP Mine didn't do any damage, so they are still working on Firestorm, though in the other game modes is so much work that I'm sure Firestorm get less priority now. (Assume)
Please take a look at 
https://answers.ea.com/t5/General-Discussion/Community-Survey-February-BFV/td-p/8750020/jump-to/first-unread-message and fill out the survey. Here you can place your comment first hand to dice.
Cheers,