I am not sure if I buy this resoning. While doom tile army is much easier to create, I found it hard to imagine major AAA game dev making same game for ever unable to create proper Ai that handles strategy and tactics with multi-tiled armies.

There are plenty of small games that handle complex armies fight with plenty units, choke-points and strategical and tactical views. Especially since the unit roaster in Civ games is quite limited in comparison to other strategy games.