Brutal rush is a double edged sword. It will hinder your opponent from hitting you some and it also seems to inhibit you, if you're also using a larger weapon. If you're thinking of using it, I'd say dexy builds are best but you should be able to make some use out of it but it should work fairly well against other spear/staff/polearm users best, especially if you are using any preps. This is just an opinion though as I don't have extensive use with the skill.

Lunge and other exotic skills will go up through use. It takes a lot of time to raise them, especially as a giant but it can be done. I've mastered a few exotic skills in the past with several of my rangers and once the skill reaches a combined 100%, they work quite well. Keep in mind that you can dual wield exotics and the overall skill level will combine. For example, wielding one weapon that can swing and you get 30% swing skill and another that can swing and you get 40%, combined they give you 70% swing, right off the bat. That means you'd need to improve another 30 times to have the skill feel as if it was perfected and if you remove one of the weapons you'd be back down to 70 or 60%. You can track this in your skills list. The exotic's skill will show up on one side and your actual skill level on the other. Usually like this "lunge (30%)(0%). "