Is there any way we could have the ability to detect/estimate weapon loadouts? There are lots of other things that would be nice to detect in addition to that, but I'd argue that would be one of the most useful ones.
Alternatively, maybe have the intel rating be an empire wide thing, and it decays as a result of new sensor designs or techs? I think its reasonable to say that an empire would generally follow certain design motifs, and thusly it would be fair to say that if you have seen most of their sensors for a time, you have effectively seen all of them.
As it is I find it hard to see myself making much use out of the ELINT modules, unless the stealth bonus is really really massive. Because as it is it kindof sounds like the enemy not using certain sensors most of the time, or spending a month developing some new one, could completely invalidate your intel gathering efforts. I tend not to use my really big sensors most of the time even as it is unless I passively detect a reason to turn them on, to avoid making a target out of the sensor ships.
e: regarding using regular sensors as the intel modules, perhaps the ELINT modules are these big old analysis computer banks you have to add in addition to the sensors they use? then they gather intel based on what sensors are detecting the enemy, and the quality of the intel is based on how well you are detecting the enemy. for instance, perhaps a percentage of how much your sensor is overkill for a particular detection. it sounds more elegant to me, but I freely admit that I could be wrong on that. im a bit sleep deprived you see.
e2: ok done editing