They want classes to be unique, each class holds a weapon differently and therefor swings it different which all require different animation. Could you imagine lets say 10 races, 40 classes, 5 weapon types, 5 unique animations per weapon type = 10,000 animations if they wanted each character to be extremely unique and something you could just look at and know what they are. Otherwise you get generic animations and character stances, the staff animation are the same as the spear, the 1h sword is the same as the mace/dagger, the 2hs is the same as the 2h mace, etc.