Hey Zizka. I like your guy, he's cool. I did a pretty rough animation edit. I think you should be a little more bold in deforming and moving the different parts of your character. In my edit I tried to make a bigger wind up to the throw. I did so by moving his body more, and keeping the movement on his arm on its own trajectory, not locked to the movement of the body. If I was going to make this into a complete thing, I would probably take it even farther.
Another thing I would do, would be to keep the animation moving after he throws the bone. Right now, he locks up while the bone is moving. As he throws, he puts weight on his front leg, bending it. After releasing the bone, he should rebound from this impact, and continue that reverse momentum into standing up normally. His throwing arm should have some follow through after he releases the bone.
Speaking of weight, try to picture where the weight of his body is. In yours, he puts all the weight on his back foot as he winds up, then it slides back as he throws. This takes a lot of energy out of the throw. In mine, that foot with the weight on it stays planted, pushing his body forward with the throw.
