Ah, the Ryu vision quest!
This is a beautiful sprite and I think you achieve the novelty you want in the rendering style. But the problems are there and they're mostly foundational, in your figure drawing and construction, as the critique in the thread says and you've also pinpointed.
Here's an edit putting the critique of the thread in action, mostly for my own benefit, I think, because my own art suffers from most of the same problems.

First of all I think on what Ryu stands for. Some of the words that come to mind are willpower, focus, drive, directness, compact power and sturdiness.
1. Here I start with a cluster edit of the face. It helps sometimes when I come in cold to focus on one area until I've gotten used to the resolution and colors in the particular sprite. I add a white eye pixel. I am not sure it helps but it makes him look more determined.
2. Compact power and sturdiness. Your sprite has a dropped guard. What it looks most like is an inbetween frame from an animation where he threw a haymaker and got parried so his arm is slapped off. This won't do! So I pull the hands up, tighten them to the body, foreshorten his right forearm, make him look focused and determined. Here I am missing the bright red of the gloves. I think for a game, I'd put that it to separate the form completely from the face.
3. This is the most significant critique not mentioned in the thread thus far: You have too much torso/groin in relation to the legs. I am not 100% on my own construction, but it immediately looks better if you flip between the two frames, for me at least. I think where you've gone astray here is that you didn't do a nude anatomy study before you clothed him. The gi obscures a lot and that hurts you. You have had similar problems with proportions, usually top-heavy sprites, keep an eye out!
I also widen the stance to give him better grounding and turn his left foot at a 90 degree angle to the opponent. I don't know karate but it looks better, I think.
4. Finish. I thought it best to actually finish the sprite this time and I was correct: I ended up increasing the darkened area contrasts a lot to give separation to the different parts.
Side by side


It's important to look at the sprite and think a while about what it's trying to convey, as a story or aesthetically. Ryu is a righteous fighter and he's super-focused and he's a wall of energy ready to burst out. First a straight jab then the step-in body shot, then a point-blank sho-ryuken and a dragon punch for the finish. I didn't learn this from extraneous 'mythos' surrounding Street Fighter, I learned it from playing the game itself. That's what you have to serve.