The way you did it in the previous version would work for the Awesome Blow included in the class, and for Vital Strike. (Which would be a decent feat choice for a Brute, I think, by the way.)
The way I proposed should be a bit more general; not limited to the "default" "attack action" that actually sees fairly little use.
I'm interested in your thinking on how the class should interact with dipping other classes, such as sneak-attackers and ragers, since this one has quite a few complementary class features. Once I know what you want it to do, it'll be easier to assist in making sure that's what actually happens.
In a way, you picked a good moment to work on this. Now that the ACG is public we can make sure it interacts with the new feats in it in the right way. We should be looking at interaction and overlap with the Brawler as well. Although the Brawler looks a lot "techier" than the Brute, so I think there's a clear niche for both.
I think I'll use a low-level Brute as one of the opponents in next monday's game, to see what it's like to fight against.