the choice of colour is more in line with the original comic book version of the suit - colour limited by printing techniques...

also if you search for superman + george reeves pictures (he was the 1950's Superman) you will notice more of a similarity between that costume & this new version..

i personally like the new suit - it's modern yet retro...

perhaps this is also only a temporary costume in the film & may be replaced at some point by the 70's style bright red, blue & yellow suit..

just a few ideas