If 343 wanted to incorporate extra melee damage with a thrust ability, it should've been tied to Thruster Pack... a'la momentum-based melee modifiers like Halo 2. Tying it to the Thruster Pack keeps things much more balanced, plus it's a little more challenging to execute and that's a welcomed challenge for something as strong as Spartan Charge.
So you thrust at an enemy and melee... extra damage is dealt and now, you're in Thruster cooldown... AND melee cooldown. If the other player lands a simultaneous melee, you both have equal chances to clean up the kill. And you're stuck... you cannot throw in another thrust to juke the enemy. But instead of having to land a headshot to get the kill, maybe you only need to hit a body shot, due to the extra momentum damage. But... this still gives the other player the chance maybe to thrust to throw off YOUR shot and maybe they'll land the headshot. Balanced... even when you get the jump.
So then if you miss? You're stuck in cooldown, you can't just dodge and recover your orientation to the enemy. It's the chance YOU took to try and land extra damage. Maybe you'll recover and survive the encounter, maybe you won't...
There wouldn't be a 3rd person animation... it wouldn't be OP... it would just be an extension of the already present melee "lunge" mechanic. Very balanced and "Halo" in implementation. Truthfully, I was pushing for this back in the H5 Beta, but we all know how the game ended up... I think Spartan Charge ended up being even MORE powerful, easy-to-use and thus, unbalanced in the end.
Thruster-Melee's in H6 please! Same idea, different implementation... UNIQUE implementation. It's not something they just ripped from Destiny to a T.