I think I understand what you mean.
I also think I agree with it, to a far extent.
But with thousands of kills, I'd think it more fun if something truly spectacular happened on kills -but quite rarely.
Something slightly spectacular, if you catch my drift, could happen on regular kills.
Oh, and it is a great idea, regardless of how often it should occur.
About the special move:
The warrior special move is a spin attack.
You could hardly implement a special killing blow in that.
That's what I meant about it not happening in special moves.
