It's my pleasure anyway here's some more stuff I found.

1
> His clsn boxes  are a little messy 2-3 is the general max from what I've heard
2
> His mid kick misses the opponent up close
3
> you have blue clsn boxes over his red ones while your intentions are good its best to give him some red over the blue so he can win some jab trades.
4
> During his "Lets see you handle this" super when its over for a few frames his clsns start going haywire.

I'm gonna try to find some more to help you make him better.

Right off the bat I noticed two things.
1
> his light air dive type move doesn't have hit sparks
2
> debug text
I'ma write down the the debug text gimme a moment.

This is turning out really nice, something i noticed though,
is that he does alot of damage on some of the basic combos. But thats just my op.
Are you going to change the voice in the soundpack to something else, the voice just doesnt click imo.
Good job though, coming out really nice, loving the man of steel winpose and music in the bg

Looking good.

The intro at 0'40 (vs Ryu) is very misaligned though, as you can even see him moving when he reaches state 0.

Also, be careful with your sprite alignment for all the crouching poses. He's often below the floor (clearly, his feet are lower than the opponent's feet) and you can use the shadow to see that. On his winpose where he crouches at 1'19, however, he's too high (front foot stands in the air if you look at the shadow).
So yeah, make sure you align his crouch pose properly, then realign all the other crouching sprites with onion skin.

This kind of misalignment really ruins the character because it makes it looked unpolished.
Good luck.

Looks great so far, but superman's left leg looks a bit bulky and a bit short during his stance, but then again maybe it's just me.

That's looking good. But as you've stated the atmosphere could probably use cleaning. But something else is that maybe when the opponent comes back down from being punched, the effect when he's hit the floor should be bigger in my opinion. Also, what was wrong with the walk anim? i thought it looked fine.
EDIT:
Also, have all the old sprites been replaced by the New 52 versions?

tumatae, did you bought permissions to make the edit?

Otherwise, I would suggest the following, when the Injustice game is released, change the voiceset.

Are you gonna improve the Bizarro mode also? or just remove it entirely?

Here's an idea for a replacement hyper, well actually two.

1. A hyper that involves punching the opponent into the stratosphere, flying up, then smashing them down back to earth. Like Supes ultimate attack in Injustice, or Kojunho & Magus's Supergirl.

2. A hyper that makes superman flying around the opponent and hitting them, not only damaging them, but also lowers their hyper gauge since he's attacking their pressure points also. This happened in Death Battle's Goku vs Superman video.