Depending on what metaphors the design team and JJ have in mind. I've argued elsewhere here that the metaphor for the new old E is found in Uhura. In this, Uhura is young and sexy, yet classy. The curved edges and firm nacelles on the new E follow the lines of a young woman, whereas the TOS Enterprise is a more mature, but still young woman, very like Uhura was in TOS.
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IMO, JJ and Co. are conscious of this. So, here, the design aesthetic for the E can't be tied in rote fashion to the 50's/60's aesthetic. It also has to be indexed to the way Uhura will be portrayed.