I think there are many ways to classify acting. One of it is implicit and explicit.
In explicit acting the character is visually/verbally presenting his accurate emotions. Like if a char is happy then its YIPEEEEEEEEEEEEE! and jumping up and down. If he is morose then its frown and heavy steps.
In implicit acting the chracter is not Visually/verbally true to his inner emotions. If the character is happy then he pretends to sad or normal while trying to contain all the energy from his true emotion. This is fun acting, lots of oppourtunities for animators to be animators.
Every kind of acting has its place even hammy acting. A good movie will have a nice texture of the various types of acting shots.