I am playing Macedonia from early on and have annexed all the greek minors without any treaties or any wars with the big boys. I now have about 20 territories and growing.
Be aware however that when you attack one of the Greek minors (except Illyria which should probably be first) you will probably be at war with all of them including their allies (usually Crete).
Be also aware that you will have frequent civil wars that, before 1.2 , would bankrupt you through mercenary spam. I made the mistake of attacking Aetolia without a Casus Belli and could never get my stability high again, which meant frequent civil wars.
Eventually you will either collide with Rome or one of your Eastern neighbors. I haven't reached that point yet, but a war with Rome while they are ahead in gold, technology and territories could spell the end for Macedonia. On the othr hand, if they ar at war with Carthage, everything is possible...
For a horror scenario, imagine a civil war breaking out while at war with Rome, and a simultaneous barbarian uprising in key provinces...
Henri
Henri