Or better yet, make his eyes squinty and put the Fliesher \S/ on him!
I was trying to figure out what was nagging at me, and I think this is it. I think of GA Superman as having a perpetual grin and squinty eyes. This image, he looks a lot more PO'd.
Which is not to say he never got mad in the old days, mind you. This image works as a "I just broke down your door, and now you're gonna get it, Nazis!" as opposed to "here I am being Superman for the cameras."
The darker colors, especially on the trunks, are a nice touch. And now you have TWO Superman for your collection...GA Supes and Earth-2 Supes.
Now you just need to do me a "Superman as Nightwing" and we'll both be happy. :-)