Trying to put together a Bithynia AAR but I've run into the same problems others have. Pergamon came at me with a majority Slinger army and their pikes are quite tough when flanked or caught from behind. This makes battles against them unreasonable. I'll have to start the campaign over but I'll use my spy to look and see which other factions need tweaking RE: Army composition.
EDIT: As far as I can tell it's just Pergamon in Anatolia. Cappadocia, Armenia, Colchis, and the Seleucids seem to have normal amounts of skirmishers. Colchis and Pontus a little more so than the rest. I'm guessing this will be tweaked per-faction as you guys go along.