You can customize their AI yourselfe by writing
your own FPI script. You can use the AI script
to make them do idle animations more randomly
so that they don't shake their heads at the same
time.
And if you don't like the look of the models then
you can use your own models.
I all depends on how advanced a user you are. If
you only click everyting together then i am afraid
that you are stuck with the stock AI but if you
take some time to learn the FPI scripting then you
can customise it a LOT.
I hope that answers your question.