just give ships a lock time scaler, 1 will mean normal lock, numbers > 1 mean a longer lock time. numbers smaller mean less lock time. you could default it to one to preserve compatibility. seems it would work better that way. theres ready access to all the data thanks to pointers to weapon and target ship (or their object signatures, i forget which).
ecm features would be cool too. id implement it as a 4th bar on the ets, you can dump power to the system, and the more you give it the better the jamming. of course this would take away from your other systems. youd probibly want a base strength value and a max value (kinda how engines work). i think it would be pretty badass. jamming would increase lock times, scan times, would intermittently break lock (frequency depends on power) and distort the radar blip and interfere with target data (such as make the lead indicator bounce around). perhaps also cause some degree of these effects on nearby ships of the same team.