Still playing a game on v 1.02, so haven't loaded v 1.1 yet. My comment is limited by that context ...
I think Stardock has finally got this issue pretty much fixed. As Glazunov1 suggests, you can now see an unpredictable variety of behaviors on the part of the monsters. This is so much better that just two or three updates ago, when the AI behaved much more monolithically (much more uniformly). In most of the older updates, almost all the monsters beelined, towards all your cities, all the time (whether you could see them or not!) on most levels of difficulty. (On the lowest two levels, you sometimes had a few monsters that idled aimlessly.) Nowadays, you get a much more unpredictable variety of behavior, which I think is much more fun, and "reasonable". To be sure, the monsters on average are clearly more aggressive, at the higher levels of difficulty.
(I've never played at Ridiculous or Insane levels, so my experience/view is also caveated, in that regard ... ) 
