Has anyone implemented this into their game? The only issue I have with it is that it seems rather fidley and very 3.x ( I was never a fan of the WOTC iteration of the rules with all the 5' stepping). It almost seems useless in a way unless it's the way I'm reading it. Whenever it's used the targets get to make a 5' step away to avoid it. THe question is if the target of the sweep choses to avoid that does that take up their action? If not why would you choose to do it as anyone that's a target will just step away unless they physicall can't.
It's used as a method to retreat, primarily. Imagine that combat begins. Conan initially sees one guard, and doesn't realize there are another six coming. He doesn't declare a fighting withdrawal. He loses the initiative. On the guard's initiative, six more guards pour forward. Conan now finds himself engaged by seven, not one guard, and realizes he needs to flee.
He can't flee because he's engaged and didn't declare a fighting withdrawal. Therefore he declares a sweeping attack. The guards step back 5' to avoid getting hit, and Conan then makes his move to the rear.
Another time to make use of it is when terrain presents itself. You have the enemy's back to a river, trench, or cliff. You declare a sweeping attack. Etc.