Had a lot of success using Epeiros as various other Greek factions. Pergamon is the most viable, largely because Asia Minor is awash with money from trade and mining, with lots of big settlements close together. Plus lots of AI factions duking it out means opportunities to exploit. Easy to defend once you've kicked the big powers out, too. Roleplaying an attempt to rebuild Lysimachos' Thracian Kingdom gives instant purpose to the game.

Also trying out Epeiros as the Bosphoran Kingdom, not sure how well I'll take to driving off horse archers.

Epeiros as the Massilians is going more slowly, limited justification for expansion beyond the immediate provinces.