Will we be getting improved melee animations with most of the guns as they seem to "poke" people rather than smash them over the head with the gun.. looks silly. Atleast when you are holding a grenade or something similar the melee animation is a punch. I think the pistol ones are good too.
Stabbing someone with the barrel of a rifle is the most effective way of using it to make a melee attack. You maintain control of the rifle the whole time, can still use it to shoot the person, and jabbing a steel tube into someone's face is actually a lot more damaging than hitting them with a plastic buttstock.