oooh Pali, that is a cool idea.
Berserker Changes
Really like that Idea Pali
Gave the Idea more thought Pali, so here is my suggestion based on Pali's Idea.
Lets add a single skill to all berserker paths, resolve.
Help Resolve
Syntax: Automatic
When a raging berserker's health is dropped to a certain point, he resigns himself to the unavoidable death. This resolve results in a sudden focus. This focus allows the berserker to forsake normal battle strategy causing his ferocious blows to ignore attempts to block or parry it.
This would mean, you can only avoid damage from a dying berserker, he would be attempting to drive your weapon or shield through you. Dodge would be the primary avoidance, but other avenues for avoidance are available.
As for at what Health level needs to be reached for it to work, I was thinking that it should start when the berserker is surviving only on his "rage bonus" HP, after all that's when he can pretty much count on not surviving.
Just a thought.