stagger duration is ~1 second? Seems pretty low for me, it is not working with 2h hammer heavy attacks, stagger wears off before you land second strike:
(Mainstay talent)
As you can see in second half of the video even Bulwark duration in 2 seconds is barely enough:
(Bulwark talent)
I believe the stagger is implemented so your party can take advantage of the damage bonus. My problem is staggered enemies fall back behind a press of new fresh enemies so capitalising on stagger seems often impossible for anyone let alone yourself.
That is only the medium stagger animation for the Chaos warrior, you need a lot of buffs to reach the heavy stagger which is over two seconds on a Chaos warrior.
This is the heavy stagger animation for chaos warriors https://streamable.com/h8r0c
In general every enemy has a light, medium and heavy stagger animation and if you want to heavy stagger CW you probably are going to need opportunist and some other power boost.