I think the biggest problem with aztec, dust, or italy is that it leaves one side at a clear advantage. This isn't a big deal when you've got a group of people who want a challenge and will keep the teams even, but a majority of pubbers simply want to stack the easier side and dont really care if the other side is getting creamed. Its all about score.
I'm personally not much for the map, but at the same time - with good teams on each side. its a decently fun one. I think their are better designed ones simply because scoped weapons are what aztec was ment for with the open spaces and such- and i enjoy a more close and 'intimate' feeling as i empty shell after shell around someone's head before i die.
Like ConGregation said, balanced maps are hard to find, they always have been. Maps like this tend to make the loosing team frustrated and very prone to /quit.