I assume you've updated this since this post was over a month ago, but did you try the method I told you about for Korelos? Basically, have the ships move and rotate towards a location on the screen and every second or so, change the location (somewhere close-ish to the player). As the player moves, it creates some interesting AI and it's all I needed for my game. People were convinced I had AI for chasing, running away, dodging bullets etc, but it was all an effect of this behaviour. It probably only works for top-down shooters, but it was a great time-saver for my game.
I can't get this capx to work by the way, but since it's old and I'm on the newer version of C2, that might explain it.