ATMs are not LRMs. Most of the times they require to have have a Line of Sight on your target to actually hit it, like Streaks do. I personally had very few chances where my ATMs were actually able to hit a target without a LoS, mostly on HPG manifold when I was on top and my target was uphill on one of those ramps. They have the advantage of being better than SSRMs at close range and being somewhat reasonably good at mid ranges (up to 540 meters), but I think that they can only be used very reliably on mediums or heavies: with assaults you are simply too slow and you can't dictate range, on lights IMHO they are not worth it since you will be spreading the little damage you can dish out. I'm not a huge fan of homing missiles, but I've noticed that these missiles heavily focuses on center torso and legs: ATMs are the nightmare of any brawling light or medium if they get caught in an open ground. Other than that, they have the same issues of LRMs: long face time, spreads damage, niche role to make it worth it.
I didn't like them on the Kit Fox, but I'm also realizing that a KitFox in anything except a support role is probably a bad idea.
Yes, pretty much: IMHO Kit Fox is best used for medium-long range engagements. It doesn't have the speed, maneuverability and firepower to survive a brawl or be useful in the long run (still thinking about it as a brawler... If you are gonna use it with 2xcLPL, stick with your team or covering their backs it will perform way better). Back on topic, I've tried again in Faction Play mine HBK-IIC-B "ATMs Bucket Challenge" (2xcATM12, 2xcERML, cAP, 3xJJ, cXL275) and man, it can deal an extreme punch close range. Lights won't stand a chance and most of the times will die at the 2nd ATM alfa strike. Mediums will last for 2 to 4, depending on skills and quirks.
ATMs are a better Streak SRM but with a minimum range. The sheer focused damage they deal out mean you're screwed in a locust if they ever get a lock on you (though I'm usually the MDD-H getting the lock ) It'd be fun if streaks locked as they did in MW4, put your cursor on the target and they track that target makes them actually useful as a light killer.