Re: Should they change the costume for the sequel?
I don't think they should change the suit.
1) The suit he has, he has for a complex chain of reasons woven in to this mythos. It is effectively a version of the family armour, given to him by his father. Where would another suit come from? The only conceivable place would be Krypton. But that would mean more Kryptonians again, and even then, why would it look less like alien armour and more like lycra/spandex?
2) The suit we got looks pretty damn good to me. Any change it require involve colour adjustment rather than a redesign.