This is what I suggest:

Celtiberians: both they and the lusotannans should be easilly killed any of the other two factions but ultamatly carthage should conquer most of iberia and both these factions. When that happens, another faction should apeear.

Barca family: and they should be FRACKING POWERFULL and if possible have some kind of script that will make it steamroll to Rome.

Koinon Hellenon should be seperated into factions, one led by sparte and another by athens I think.

Asia Minor needs another faction, Pergamon?

Roman rebels

Seleukid rebels.

4 more random barbarian factions.