I think it will be hard to hide the joints, its the curse of this technique i'm afraid.
To make it more fluid i would try to add more second movements/animations. On this character i would ad it to the face and hair. What i mean with second movements is a movement that ads to the first big movement and that is more subtle.
Like the hair could keep going down for two - three frames and then keep following the main movement of the head. Same on the way down it could keep going up two-three frames. Now it looks rock solid.
Also try distorting his hair and chest height with scale. Just a little bit when the body is at its lowest, Maybe .95 or .90 Just a little bit, barely noticeable but it ads a lot on the whole. It ads a bit more weight to the character. Like the sensation when he puts down his left leg, it looks like he puts his whole weight on it, thats nice. 🙂
