There are some really neat tricks you can do with Arco.
My first arco game, but I really like astrologers with penetration items and large astral income from clam hoarding.
Any astrologer can mind hunt with an astral skullcap. Your priests can heal feeblemindedness to put the astrologer back in commission even if he gets his silver cord severed.
I adopted the policy in my SP game that any invading army that doesn't get astral mages will lose all its commanders the following turn.

It's not so hard to defeat your enemies when you can turn their armies into sitting ducks and not have to guess where they will move next turn. Sometimes I have one or two astrologers mind hunting any large concentration of enemy troops even if I don't know whether there is an astral mage due to healing.
Mind hunt makes capturing even hill fortresses a breeze provided there are no astral magi present. Even if there are...you can send an astrologer with a couple of decoy hoplites in to cast astral duel and then retreat. No astral mages...mind hunt to your heart's content.
It's amazing how much fun it is to kill enemy pretenders from afar.
