Oh well. We can't really expect that Minas Tirith is to be a quasi-Constantinople or any other city right? That would've robbed the wonder of Tolkien, if he was a plain copycat. But as there is nothing new under the sun, and that in lit classes Tolkien is one of those writers who follow (whether they intend to or not) archetypes. And then notice the trends of socio-politics of cities, real ones and those that are fictional yet well-written: they follow patterns that are a little different and at the same time a lot different from one another.
Cheers from little Lindale.