It works and it doesn’t and it’s very easy to why. The cinematic sets up rules that it quickly ignores for the sake of the climax. It could have been a lot better if it just followed its own rules.
Rule 1: Sylvanas doesn’t want to be hit.
This is established by how she if very intent on avoiding Bolvar’s attacks, this is true to form and makes sense because she is a ranged fighter. We, the viewers, immediately sympathize with this challenge of ranged v.s. melee.
Rule 2: Arrow placement is important.
We find out later that the chains come from arrows and we know that these arrows do nothing to Bolvar, but thanks to how the camera focuses on the arrow that goes into ice, we can assume the arrows are important.
So that’s the set-up, where is the pay off? Well there is none, which is why the cinematic doesn’t work. We can gripe about lore, and power levels all we want but the cinematic doesn’t even work within its own self-contained bubble.
Rule 1 Pay-off: Bolvar does the ice storm in order to get within melee range of Sylvanas. This SHOULD be a pivotal point in the scene, from what has been established, Sylvanas should be getting knocked around at this point, but doesn’t. Showing that the established concern for being at range was unnecessary.
Rule 2 Pay-off: The placement of the arrows becomes apparent; we see the chains appear in significant ways that stop Bolvar. However, when Bolvar swings his hammer, chains appear from nowhere to stop him. Now we wonder, what was the point of the arrows? Why didn’t Sylvanas just start off with the chain if they could come out of nowhere?
At this point you have lost the audience, this is very common in today’s media; a character breaks the rules of the world in order to seem more powerful. It never sits well with the viewers because we feel like our time learning about the characters and the world has been wasted.
Solution: let Bolvar hit Sylvanas within the storm, show Sylvanas more concerned with where the arrows are and where Bolvar is. Show Bolvar able to break out of 1 or 2 chains early. Then when the chains come it will have a payoff and Sylvanas’ victory will seem earned and a result of her careful planning.