Hope there's a mix of ragdoll and animated deaths. I don't like pure ragdoll, at least not like in Bethesda games. Look awful, the way the bodies land. On the other hand, purely animated deaths are not good either, but I haven't seen those in a game for a long time. I think Left 4 Dead did the death animations well. The infected die, they do a death-animation where they stumble forward or fall realistically. During this death animation, they still react to gun shots. You shoot them as they fall to their knees, they will jerk. Once on the ground, they turn ragdoll. I like how this is done.
The reason it looks weird in the Kingdom Come trailer, in my opinion, is because the animation is so slow. If it's faster, it probably looks more realistic. Had he turned ragdoll right as the sword hit his face and killed him, his knees would bend and he would sit on his ass most likely. At least that's how it is in games with pure ragdoll (looking at Bethesda again) - knees bend, fall on their ass, legs spread. Looks dumb.
I also play a lot of Chivalry, they have death animations too like if you shoot an arrow in the throat of a guy, or if you cut off a limb. Even if you cut through people like butter in that game and it's not really realistic, it still looks cool. It's awesome to cut off someone's leg right under the knee, he jumps on one leg, grasps for his stump and you kick him in the chest so that he ragdolls and fly backwards. And the "arrow to the throat" animation is the best one. Really sick gargling noises.
I also hope that there will be animations of wounded people. If you stab a guy in the guts, he'll fall to the ground, still alive but not in a condition to fight you anymore. He could roll around grasping his wound and scream, he could lie down in foetal position and whimper, or he could slowly crawl away from danger. Of course, if he's in that condition, he won't survive, so it's pretty much a death animation for him. You could go up to him and put him out of his misery. A dagger would probably be the most humane. As opposed to warhammer to the forehead or cutting his head off with an axe.