A reproduction of Alexander would be too cheap and unoriginal from their side, so my opinion is that perhaps they'll go for the period after Alexander's death, focusing the map on Italy, Balkans, North Africa, Anatolia, and part of the Middle East.
So it's either the Rise of Rome, Epirus (under Pyrrhus), Carthage, Ptolemaic Egypt, Seleuchia, or Macedon. Probably something similar to DEI's Macedonian Wars but on a larger scale. Or perhaps that's my wishful thinking
But you gotta admit that there was some really tight competition among the aforementioned factions so it does fit into the idea of changing the history within a short period of time, an alternative to the mighty Roman Empire. Perhaps they can throw in there the Celts as hordes in the Northern borders of the map and there you go, a best selling pack (for me at least).