I've said it before and I will say it again.
The current ECM features are a direct result of a lack of features in the other support electronics.
When we first got ECM added to the game we had TAG that had 450m range and it tightened up LRM volley spread concentrating damage.TAG was useful enough to be used but was not a big enough concern that a team with TAG was looked upon as having a significant advantage.As such TAG was not viewed as being a big enough threat to have to counter with ECM.
We also had NARC.And NARC essentially did nothing or more precisely it did very little for a very short time.Essentially NARC was (and still is) a waste of it's tonnage and hardpoint allotment.NARC is not seen in widespread use because it's basicaly junk.And since it's junk it is of no concern as a threat to the enemy that the enemy need not concern themselves with countering this nonthreat.
We had Beagle Active Probe well BAP was only widely used by streakcat pilots to use it as a means of countering the counter to being streaked into oblivion.Can't lock onto shut down mechs,unless you have a BAP equiped.
BAP allowed shut down mechs to be detected and locked onto and provided a slight boost to sensor range.Not a big enough concern for players to put any thought towards countering BAP effects because BAP's effects were bearly worth notice.
Artemis augmentation was still in it's infancy when ECM was introduced so it's a tad difficult to truley determine how much Artemis does most of the time if... A) no one is using LRMs because of ECM or

Artemis is not functioning because of ECM.
So if BAP,TAG,NARC and Artemis were all suppose to be countered by ECM yet most of these support electronics didn't even do enough to merit their use never mind countering their use ECM needed more features above and beyond a simple support electronics counter measure.
That is why we got this monsterous Square Peg ECM feature.
ECM is a Square Peg that the developer will not round out.They just keep trying to hammer it into the round hole of mechwarrior online.
I fail to see the wisdom in altering the entirety of a game to make one feature fit when simply altering the out of place feature would be a more elegant solution.
Yet ECM has already caused alterations on several aspects of Mechwarrior Online.
First the Developers were concerned ECM was to powerful for use on any and every chassis.The Developers altered the mechlab to allow only specific chassis to select ECM as an option.Now mech chassis selection is influenced by ECM.
Next they changed TAG into a means of countering the sensor jamming of the heavy handed ECM feature.
After they tried that it was determined that TAG needed it's range exstended to 750m from 450m.So rather than alter ECM's effects we had TAG altered...TWICE.
It was later determined that ECM was still very potent and somewhat unpopular with many of the players.The developerd did not alter ECM.Instead the Developers added in Modules to diminish ECM's sensor jamming range effects.So now we have ECM causing Mechlab,TAG and module development and use to be effected and still no fundamental changes to ECM that apparently needed to be made less effective since it merited all of those changes in the first place.
So now after altering mechlab,TAG (twice) and adding in modules specificly designed to limit ECM effects the developers apparently noticed that all of this was still not enough to curb ECM so PPCs were granted additional effcts to scramble ECM.
So again rather than review and redesign the features of ECM to suit the game another feature of the game was bent to serve the overly bloated ECM features.
Now we have an ECM feature that infects nearly every aspect of MWo.
What chassis? ECM has an influence on this choice.
What configuration do I put in my chassis? LRM,Streak,TAG and PPCs use are all influenced by ECM.
How do I manuver my mech? ECM effects how and where we pilot.Do we stick close to ECM to keep within it's bubble? If we are the ECM how do I manuver to maximize my teams benifits?The use of ECM has limited inovation in tactical manuvering.We must be mindful of ECM and if we are benifiting or suffering under it's effects and where to move to gain the benifits or remove the detriment of ECM.
Even what we shoot at is influenced by ECM.Do we make ECM mechs a priority or do we select targets based on other criteria? ECM impacts what we shoot as well as where we manuver.
The strategic meta game is influenced by ECM.Group composition is heavily infuenced by ECM.When building a competative team we need to think,Do we have enough ECm? Do we have enough to counter enemy ECM? do we need more ECM or more TAG/PPCs?
ECM has deffinatley contributed to the ponderously high probability that each and every match you play in will included a Splatercat or two or three or four.ECM has deminished the disadvantages of using a specialized mech like the 6XSRM6 Cat because it can be sensor cloaked by ECM vastly improving it's chances of closing in to it's ideal range.While simultaniously vastly reducing the strong counter to short range Monsters the LRM.
Most players do not even consider these far reaching effects of ECM when they debate for or against it's current implimentation.
ECM has way to much influence.Developers seem to be bent on hammering the entirety of mechwarrior online to suit ECM instead of shaping ECM to fit the game.