Uh, that would definitely change how good it is.
Without the drones, the Tempest becomes nearly defenseless against both fighters and missiles, unless 1 of the 2 medium slots are sacrificed for a (bad) energy PD gun.
HEF is a force multiplier, +50% energy damage for a short period of time, which translates to 1.5x shield damage, about 2x armor damage, and a little over 1.5x hull damage. IOW, those 2 energy slots hit like anywhere from 3 to 4 energy slots for a short time window, and the Tempest loves short-time windows.
Plasma Jets doesn't sound like a good idea. Tempests would become less fatal, yes. They'd also become far slippier and more annoying to catch in the first place. Even if I agreed with the premise that Tempests should be nerfed, I wouldn't want a change to Plasma Jets simply because that sounds almost as annoying as trying to catch and kill old Hyperions.