I've liked the idea of being able to go unarmed myself. I've dabbled in trying it already, by having the JG guy ram into enemies. It causes them both damage, although I haven't tested this in JG 0.1.17 yet.
My personal idea is that pressing and holding the attack button without a weapon simply turns your weapon hand into a short-range, bare-minimum-damage weapon that relies entirely upon yourmomentum, plus your arm strength and "damage" stat, to do anything. Just imagine swinging that hand around while the JG guy's notoriously floppy arms follow along as a tether.