Yes and no. I am only into the 2nd game since beta launch. The first game I was attacked like crazy---not so much around turn 25 but certainly before 100. I lost one city before I got a handle on the problem. This second game my cities have only been attacked once or twice by monsters. Maybe it's random? I wonder if monsters are attracted more by cities that are not well defended? they continued to attack in the 1st game even after I was stacked---which kinda became a near waste of time because they no longer won. The attacks just detracted from my main objectives. Sorry I haven't played enough to give you a more definitive answer.