If pull down checks, guard sweeps, and strikes to your opponent's head and body don't work, you're problem isn't that you're training the wrong techniques. It's that you're not training enough.
These techniques work. But you have to spend time squared off with an opponent, grabbing and pulling each other's arms and trading shots to the head and body. You get better by practicing. There are lots of techniques I couldn't do effectively when I first learned them. Like the front kick. I did more front kicks. I got better.
The freestyle techniques are like any other techniques. You have to set them up. You have to apply them to the correct context. You have to take advantage of timing, distance, and angles. You can't just throw them at your opponent like mud on a barn door and hope they stick. You have to be smart, and you have to have trained hard.
But if you are, and you do, the freestyle techniques work. The reason fighters grapple is because it's hard to disable an opponent with traumatic striking. You have to hit them in the head and body, and their limbs get in the way. The point of the base freestyle techniques is to pull their limbs out of the way and strike to the head and body. That isn't unique to kenpo. That isn't unique to asian martial arts. That's basic, universal fighting strategy. If your opponent leaves his lead guard hand out away from his body where you can swipe at it to knock it out of the way and follow up with strikes to vulnerable core targets, you do that.
If you can't make that work, keep practicing. If you think it doesn't work, keep practicing. Most of the people who complain about it will either give up on martial arts all together, because it's hard, or they'll just drop out of kenpo and go train in some other art that will teach them to clear their opponent's guard and strike at his head and body.
And then they'll probably brag about how they've finally found something that works.
-Rob