I think the Roman Empire at its greatest extent would include 140 regions on the map. It's still pretty easy to win in this game though it does take longer than any other previous TW game I've played. I think that has more to do with the map feeling more spread out.
Cultural and Economic victory conditions differ between factions, but they're basically slightly less regions than a Military victory plus a certain number of trade agreements and income level (Economic) or building certain cultural buildings (Cultural).
I found the blitzkrieg tactic to be viable for military victory. I started as Iceni and once I had a foothold in mainland Europe I tried to capture at least one settlement each turn and declare a new war once every 2-3 turns.
"I just wasted a bullet. Don't waste your life." -Big Boss