So... anyone here watch Extra Credits? An episode they did recently has very direct influence on how ECM is borked.
http://penny-arcade....de/counter-play
The episode is very entertaining, and I advise you guys (players and devs alike) to watch it. But if you don't feel like it, I'll summarize.
If you want to put in a feature (such as ECM), think about how it's fun not just to USE but also to fight AGAINST.
So, ECM. How is it fun to use? Well, it screws with your enemy's targeting, prevents LRMs and SSRMs from being effective, and prevents your enemies from getting detailed damage info and coring you easier. So the use is pretty darn fun!
But how is it fun to counter? Well, to counter ECM you want to... um... use ECM. Or a TAG laser, to some extent. But wait! If you've got a TAG laser, stay over 180 meters from their ECM 'mech, or they will automatically counter your counter. Really, the only EFFECTIVE counter is your own ECM. TAG is simply not an effective counter because it requires constant LoS targeting by a 'mech that is over 180m from the enemy, but not over 450m. I mounted a TAG on my 'mech just for that purpose and it is highly ineffective. Largely because it requires me to constantly target an enemy, which I can't do when there's five of them and I'm in an Awesome. Because they'll core me in about two seconds flat.
So how is ECM fun to counter: Answer? Unless you have an ECM-capable 'mech, it's not fun. Not fun at all.
My suggestion: Have an item that can be mounted on ANY 'mech that PARTIALLY counters ECM. How about this: if you have BAP on your 'mech, then your targeting computer cuts through ECM. (Possibly at reduced range? For this example, I'll go with one-half standard target range)
So, if you've got BAP:
And you're over 400m from an enemy protected by ECM: You can't target them unless a teammate shares info.
And you're over 180m but under 400m from an enemy protected by ECM: you can target them normally and share target information.
And you're under 180m: YOU can target them normally (including missile lock), but you CANNOT send that information out to your teammates.
As I'm thinking about this, I'm worried that might over-nerf ECM, but that is most easily balanced at the targeting range. My first thought was standard target range (800m), my second one-half (400m). Right now I'm actually considering either 200m or 250m. (200m: Standard targeting range against ECM. 250: Standard targeting range against ECM + 25% BAP bonus).
So this would install BAP as a PARTIAL counter to enemy ECM, preventing some of its painful effects.