I think EMP is ok as it is.
It provides energy a good amount of drain, and a decent response to the high energy phis mechs that hunt them.
Befor it, high energy mechs mechs could not be drained, and pounded energy mechs in less then 2-3 turns, now they get a “get out of jail card”, intem, that gives them a fighting shot.
It was why the devs made it, to find a solution to the problem of a single element dominating the others.
Sure there are counters to it, but are not the traditional ones.
In my book, it is a decent item, a hell lot better then Heatbomb.