First of all, there is a reason to kill anyone you see since everyone starts with a few items of value and could potentially carry something rare that they looted. People who looted enough should be smart enough to avoid combat, whereas recently spawned people don't have much to loose, besides time.
Using a melee weapon should be powerful, since you aren't sniping someone witout risk, you are right where the opponent can strike you back.
On the other hand, being more focused on combat should reward the user more, so proper hit detection would be nice, so a careful player would strike the opponent in the head, rather than spam-swing in hopes of his hits registering.
Or you could carry a m4 with all the attachments on it, enough ammo to kill an elephant, and wear kevlar instead of avoiding combat.