I have said it before and I will say it again - it is absolutely hilarious how people with ZERO qualification talk about a game engine. Stop blaming thing you do not understand, don't be so ignorant ffs.
How do you come up with this kind of stuff? Have you actually paid any attention to combat animations in Rome II and that it follows the very same principle of soldiers being able to kill others with a single animation? It DOES happen that a soldier may fight a 1v1 and then he gets gutted by another. So basically the only real difference is that Rome II also has a set of animations for more dynamic deaths... Just like all of the TW games from Medieval 2 onward.