QuintusSertorius gave you a good reason why you have to cheat. At times you must move other factions stalks around, where they can do damage, and away from a weak faction. Force diplomacy is good to protect small factions, give them time to conquer the "Free People" settlements. If you dont cheat, factions like the Ptolemaioi, Epirus, Koinon Hellenon, Lusitanni and our beloved Rome will conquer all. Its not nice to fight it over between three or four super factions.

Use Force diplomacy and move_character to preserve other factions and have fun, never cheat to make gameplay easy to you.

Cheers.