AC3 wasn't bad. I liked the added weapon animation of flipping it around like a baton but they did simplify it from AC2 and Blackflag appears to me to be even more simplified. They've just taken too much control ability away and don't know why. AC2 seems to have that sweet spot.
In AC2 when you take a flying leap off something, your character will automatically grab a ledge if its available or possible. However after that, if you let go of a ledge, its up to you to re-grapple otherwise you'll keep falling. From what I can tell in AC4, that's all automatic now. If you simply let go of a ledge, your character automatically grabs the next one. I don't like that. I liked how in AC2 you could be scaling some tall stone building, choose to leg go, then fall a couple of stories and then grapple once again onto a ledge as you are falling past of your own accord and input.