Brute is such an odd ability, as it feels like it equates to the same thing as altering a model's stat block.

By contrast, Mighty also makes a change but throws a condition on that modifier.

With that said, and given that a model being unruly is currently identical to a model that has activated, I wonder if you could do something thematic and alter the brute rule so that a Brutish model gets improved defense when unruly, thus adding a condition to the ability and giving the unruly condition a little more impact.

A brute is one that doesnt behave and is hard to put down, so it feels like it works and makes their mechanics and use a little more interesting.

Just a thought. :)

I agree, I don't really understand the point of Brute. 

I really like your suggestion of Brute altering Defence stat whilst being unruly.

Before reading your comment, I've been playing Brute with this ammendment:

“Brute (X): Enemy Warriors in Melee suffer a +X penalty to Defence rolls.”