IMO, there are 3 ways to balance BA:
1. Nerf their Armor (or)
2. Nerf their JJ recharging speed.
3. Nerf damage of their weapon and boost damage of their explosives so they use mostly explosive and SRM vs Mechs.
I respectfully disagree.
Their armor is fine, they just need to have their armor displayed properly. In cannon they did take heavy weapons or sustained fire to take down. (just like now!)
They were jump jetting bunny hoppers, made to bounce around the battlefields to pester and dismantle enemy mechs and vehicles part by part (just like now as well.)
And via Cannon an Elementals standard weaponry, was 4 SRMs, Small Laser, and an anti infantry machine gun. Now, their SRMs were nice, but their main weapon is the small laser, you cant exactly nerf their main weapons

I am a (fairly) dedicated BA player, i can get some good kills with it, but their explosives are kind of a joke, with the lag the way it is and the way they arc it is very hard to actually peg a mech with the grenade.