I'd agree heavier over light any day...however, I build my setups to give a good combination of speed and momentum depending on what I'm hunting and that's whitetails for me most of the time. Deer are relatively thin bodied animals and easy to shoot through. So I pick a combo that also allows me some error in distance judging or the animal ducking. Otherwise, most deer hunters would just be heading to the woods with moose setups.
Good discussion.