Metropolis the city of tomorrow sounds impressive, until you read a comic and see that it is the city of today (boring). Metropolis would have to be a reflection of the future, but not only in small details but in a big way. If we believe that in a few years there will be flying cars, Metropolis already has them, policemen with iron man armor (not a special team, all the police), Metropolis already has them, Metropolis would have to be a decade or two ahead.
which is your metropolis.