A good grappling system would be great, but its not going to happen with modern technology.
Real unarmed fights are much to complex and fluid to model with a mouse and keyboard.
Trying to grab a weapon off someone, or knock them to the ground, smash their head into the floor, choke them, whatever, would require too many different buttons, and could not be realistically modelled.
Grappling relies primarily on strength and manipulating the other persons body. The only way "strength contests" work in games, is button mashing, which is terrible, and theres no way to operate 2 arms and 2 legs with 1 mouse and one keyboard in any decent way.
When we have full immersion video games, then it would be great, but as such it would be too "gamey" just to have a punch or grapple button.
At best they could have it so sprinting into another soldier knocked him over/knocked the weapon out of their hands, but even still it wouldn't be great.
Otherwise spade/knife is the only realistic option for okay melee combat.