This is I think the biggest problem with the game right now. It's ridiculous how they all stack on top of each other, but I don't think collision is the only problem. The way everyone slides around like they are floating, and start vibrating as they all try to push each other out of the way. It doesn't just look broken visually, it changes the entire feel of combat. That gamescom footage looks basically how warband was, so much better. It's like a completely different game. Actually it looks great I want to play that game.
Same thing happened to starcraft 2 compared to the original, they "improved" the pathing/collision so everything flows like water, but it completely changed the gameplay for the worse. The result was the same too, especially big battles were over really fast and you didn't have much control over them. You just send your blob and hope for the best.
Here we have 250v250 battle, over in seconds. The actual combat only takes about 45 seconds.
Watch "over-in-seconds" on Streamable.
streamable.com