You know actually, to be honest to me it looks good as is. It's still metallic and just doesn't have a high gloss finish.
Watching some scenes from the movie, IM never really looks that glossy and has more of a metallic shine like in one of the more recent pictures sarakawa posted.
The following picture of the Mark VII bust by sarakawa looks similar to how IM looks in the pictures below it.
Now that I think about it, I remember seeing the Mark III bust in person recently and it wasn't exactly super shiny/glossy. I also remember there were people using car wax on their busts and buffing them to get the results they wanted. If you guys want a super glossy IM bust, the Mark VI Legendary Scale Bust looks like it has a glossier finish.
Regarding the arc, it's actually not too big a deal for me. I'm just curious to see if they'll make it look like War Machine's in the end. If it's the same as War Machine's that would be great but it is just a painted version of the details of the arc and not actually sculpted right?
The problem I encounter with HT Iron Man figures is that yes they do have the arc components on the figure but when you turn the lights on you still see the arc which doesn't look that great. With the solid white in the arc window the light is uniform and actually looks like it fills the window. Personally, I'd rather have it look full.