It's not worth it in the least. America in MIITW just shows that CA put little to no effort on it. There are some mods that are working in making it better though. Up at the TW Center, I'm working on a mod focusin on the New World. ;D
But yeah, you need to wait to the Columbus event, then you need to build the proper buildings to get the ships you need. Then you can sail across and kick some Aztec ass. If your computor can handle all the jungle spam you have to go through, that is.