Missiles currently have a nice system of weapon systems -> counters -> counter-counters. Beam/energy weapons don’t.
It would be nice to have the same kind of rock-paper-scissors for energy weapons. One path to doing this would be to make the ECM shock mechanic disable energy weapons specifically. If the duration of the shock lasted a bit longer and impacted only energy weapons, it might become an interesting and balanced mechanic forcing more strategic design choices during ship and fleet building. With the shock beam and missiles plus the anti-shock cruiser device, everything’s in place for making a beam weapon analog to the tactical decisions around using missiles and missile defence.
Regardless of whether the above has merit, I’d like to suggest renaming the shock mechanic from ECM to EMP or the like. The shock mechanic and the anti-missile mechanic are two distinct effects and would be clearer with different terminology.