Uhm, at first I was very disappointed. Hoped for this to be 1/6, there are quite a couple good comic suits that I'd like in 1/4 scale and this really isn't one of them.
I think that the design hardly blends with the rest of the Avengers, too raw, simple, old school, when all the others have had their costumes modernized.
BUT. Shroudan already said that they're gathering inputs to give this thing the extra edge, and while I hate diaper-panties, I also have a thing for retro sci-fi.
So, let's start with a few considerations. Imho, the trickier part on this one is going to be the helmeted head. It really looks funny in most of the comics, and it's the weakest spot of the suit, the spot that makes Iron Man look like Tin Man.
For reference, here is a good pic I'd use as ispiration.
Pose is good, not original, but good for the character. The destroyed background is already there and if there is a statue that may need half of a destroyed car on the base to add dramaticity, is this one.
Note that, as I said, imho the head is the weakest spot, the long thin neck with the bunny faceplate is all kind of wrong. Also, those quads are HUGE.
My suggestion would be to take that pic as reference, but with this helmet head:
And possibly, get rid of the classic diaper-panties and use the above pic as reference for the crotch piece.
Then, last suggestion. You want to make it modern while keeping that design - use hexagons. Hexagon patterns are synonim of sci fi and can really give an extra edge, use them.
This is an unused concept art for the IM3 Mark 42, note the hexagon patterns on chest, abs and legs. They make a world of difference and I bet that many wouldn't have disliked that suit if it was more similar to this concept art: