I think the problem with your fireball animation is that he's making a very violent motion but is unaffected by it. You don't have to be a great physicist to be a good animator, but there are two rules you MUST remember when animating:
1: Bodies in motion tend to stay in motion, and bodies at rest tend to stay at rest
2: Every action causes an equal and opposite reaction
For almost any animation this is all the physics knowledge you need. You can make an animation more or less "stylized" by exaggerating or downplaying these laws.
Here's my edit:

It's slightly exaggerated to get the point across. Mine looks like it has more frames then yours but it actually has one less! I took out one of the blurred arm motion frames and added a few frames of recovery motion after the swing. He moved his arm with a lot of velocity so he has to use many different muscles to compensate, and he can't immediately stop moving his arm, he has to fight the inertia that he put into it. Try making this motion in real life and you will see that you have to push against your own velocity to stop your arm, and it actually bounces back and forth a little as you fight to regain control of it. This is applying Rule 1.
If we were going to be sticklers about reality I would say throwing a fireball this way would actually make it quite hard to control. thrusting the palm forward would allow for much better aim. But that's getting pretty anal and kind of takes the fun out of fireball-throwing anyway.

Anyway after the hand swing, the explosive force of the fireball actually pushes against him, and you can see his coat and hair blown back a little bit as the fireball pushes away from him. Remember, it's propelling itself by explosive force! All that energy will push against whatever it contacts - this is an application of Rule 2!
Also take a close look - after being blown in their initial direction his hair and coat actually swing past their original position before they lose momentum and come to a stop - there's Rule 1 again!
In games like Street Fighter 2 they couldn't show this because they didn't have enough memory for those few added frames. But it makes a huge difference. (Notice how in later Capcom games they started putting these frames in and the animation magically becomes so much better!

)
(Also I would add a highlight against the front of his body from the light cast by the fireball as well, but I didn't want to cover up the basic animation in my edit.)