I've seen and tried a melee action of a sort in FDFmod for Arma Cold War Assault, in which in one MP mission you were actually able to use a knife against an enemy once in range and the stabbing was done using the Action Menu (automatically appearing when in range). The stabbing itself was never animated, except for the sudden death of the enemy. You had the knife with you even that it wasn't listed in your gear. The feature wasn't that perfectly made as you were able to stab the enemy through a steel door, a bunker wall or even round a corner, even your back facing the enemy.

I think the problem here is how this should (and can) be done in Arma 3 in such way it will actually work. Action Menu isn't practical in this case.

As with Streaks, I agree that this is a feature worth thinking, but I'm not expecting this to appear any time soon as there are tons of things that need fixing.