His tiberium flechette gun is like designed to do it. Just aim at the upper part of the body, and if you're close enough, it's a guaranteed kill, no matter what character it is. The spread on that gun makes it so that if you aim for the torso, you will hit the head (and god knows how big the NOD have their heads... Just look at those soldiers!). Be it mobius, gunner, mendoza, raveshaw, havoc, none of them can whoop your ass if you have good reflexes (by this, I mean that you start firing before, or at the same time as they do), considering of course that you are within effective range (which is quite small... a little bit further than a volt gun).
It takes 3-4 seconds to kill a person with him (if you have good aim of course), even if you don't kill the target it still takes damage from tiberium, and he has enough armor to take 2 shots from the most powerful weapons. It's an anti-infantry unit though, so don't expect anything spectacular with buildings and armor.

I don't see why people qualify it as a useless or newbie character. In the right hands, it can be devastating. Like a rapid-fire shotgun with longer effective range.