This is a royal pain, even moreso if you are melee dealing with ranged enemies that have it. I can honestly say I would not be surprised if the fear chance on their hits is ranged somewhere above 75%.
2: Mortar + Waller = Removing Mortar's Deadzone
Enemies with both of these (or if you go for some fun with 2 packs, one with each), can effectively shoot within the Mortar's deadzone if a Waller's wall is blocking it's path. It will not travel over the wall, but instead reach it and follow it to the ground.
These last ones aren't exclusive to champions and elites, but are related to enemy behaviour.
Ranged enemies that will run ENDLESSLY until they clear a minimum range with you. Fallen Shaman, Wretched Mothers, Blood Clan Impalers (Can't recall any others atm) are all guilty of this. If you play melee, you nearly have to funnel them into a corner to get at them, have bonuses to movement speed to catch up to them, or have some form of movement-based skill on your bar to reach them. This needs to be changed. Their behaviour isn't even anti-melee, it is like they are trying to imitate Treasure Goblins, without the reward.
As well... can the Fallen Overlord type enemies NOT buff a champion/elite pack of the small Fallen guys with increased attack speed and movement speed? That is just unfair to tack onto a champion pack already with 4 affixes.