The thing with morphs is that they don't have all attack animations. This is usually a problem when using special sequences (SQ) because then you don't seem to do anything at all while you're attacking (SQ skills are for example enfilade, dualweilding skills, SMG, etc) - but they are actually doing damage, it's just a display "bug" - I prefer to call it a feature because it will never be fixed (it's impossible to make animations of diablo/baal dual weilding or doing any other SQ skill animations)