Why not,seems like the logical next step, vaulting in ArmA 2 was a huge yet incredibly simple leap forward tactically wise in the simulation, players no longer dreaded the mundane picket fence when it came to engaging targets in an urban space. Definitely a lot of testing will be needed for such a feature since even something as simple as vaulting low objects has been known to be a bit clunky at times in ArmA 2.

I personally am a bit on the fence with the issue, I have in ArmA and Arma 2, played matches where I have ran completely out of ammo, usually at that moment I make a beeline to the nearest corpse and grab what I can, problem solved. However I have had a moment before where I was locked into a long engagement inside a building with my squad in multiplayer me and one other ended up having a last stand there while we waited for support, we ended up getting overrun after running out of ammo, would have been nice to ambush them with melee as they came up at us.

The only other draw back I see with adding melee is that even in other realism games that have a melee feature, players tend to try to charge in and melee other players when the opportunity presents its self, even if the melee feature is not a guaranteed one hit kill, these players tend to do it as a "for teh lulz" thing which can be kind of immersion breaking at times.