I’ve found Target Painters and ECM Beams to be very effective but I’ve also noticed what appears to be a strange bug in their behavior. If there are more than one target painter or ecm beam on a ship then same type turrets all fire at the same target when they fire. That’s a sub-optimal behavior for either system since there is no apparent benefit for multiple target painters or ecm effects on a single ship or missile. Would be nice if multiples of those turrets would always fire at different targets. Currently any more than one of each on a ship is a big waste, but there’s nothing to tell you that they lose effectiveness.
I agree with this, target painter’s especially would benefit as it would mean they could be used on packs of fighters (with anti fighter missiles).
Agreed. Though unless battling fighters I consider having my fleet targeting more than one ship at a time to be sub-optimal. 
This will be fixed in 1.17
hooray!