If it's not enough that the devs make aiming far more difficult while utilising jump jets they could add recoil to weapons from the projectile category based on the size of the gun. Like if you fire a big gun like a gauss rifle while using jump jets you could lose your balance, tilt backwards and fall back first into the ground and receive some damage for that nasty trick. When it comes to energy weapons with no recoil like lasers, they could make it unprofitable to fire them while jumping by giving jump jets an aggressive heat spike that would, however, dissipate fast so that you could fire your weapons like usual when you are back on ground...