Even after the fix for the Golem, it doesn't seem like there's a point to Brute being a special rule, over just having a higher Defence. Am I missing something?
You're right. It's a bit redundant. But with this ability, Golems are the only models with a 4 in defense except champion and uniques.
Another interesting idea is, to decrease the enemy Defence instead of increasing the own. Makes the ability a little more stand out.