My friend and I are building a huge floating island currently about a hundred blocks off the ground, which is being quarried to provide building materials. The combat update gave some rather interesting abilities to the new mob AI, for example skellys will now shoot straight up or down when they didn't before 1.9.

While I was building, I saw a witch down below that was taking damage. Upon closer fly-by inspection, it had targeted my friend and was repeatedly attempting to hit him with poison. To re-iterate, the witch was trying to throw a potion over a hundred blocks straight up. But splash potions only go up about 6 or 7 blocks before they fall and effect whatever is nearby, in this case, the witch who threw it.

Perhaps it would be wise to give certain ranged mobs the discretion to know whether a target is actually in vertical range? Come to think of it, some skellys were trying to shoot me from out of range not too long ago on a different world.