The main thing to include in an expansion about Alexander the great would be a mechanism for empires to actually crumble or atleast shatter. I would've figured the Diadochi period as more likely as the theme for an expansion but one that sees both the rise and fall of Alexander's empire (and the Persian empire for that matter) might be even more interesting.
The presence of such a mechanic would hopefully make gameplay more interesting throughout the EU:Rome era.
The presence of such a mechanic would hopefully make gameplay more interesting throughout the EU:Rome era.