This mod aims to update much of the 2004 Axis and Allies RTS game to modern day warfare. A new campaign is planned along with a new WW2 mode, and current nations to be involved include China, Russia, the United States, the United Kingdom, EU, and many other countries. Infantry and naval combat are being entirely reworked, as is the game economy.
I've been adding a few large cities to complement capital buildings on certain WW2 Mode provinces. NYC is one of them, and has a very high resource value due to the number of skyscrapers and office buildings (each of which add +5$). The AI has been/is being reworked to value cities more and these are cities they wont give up easily.
you can't really have a Corps HQ spawn -inside- of a city. as Wordsarecool pointed out you don't have a lot of control or precision in RMC maps. you can set up basic parameters to limit where things spawn... but that's about it.
Berlin, for example, might show up in one of four different layouts. this layout could get cut short by nearby mountains or water. you're not likely to see the same version of Berlin two games in a row in an RMC.
a NYC custom-map could be made fairly easily with the editor though. you just couldn't do it with the Randomly-generated Map Creator files (RMC)