Speaking about water, would it not be interesting with the underground management section to create a humidity concentration wich would vary depending on where you are on the map, and which would give perks and disavantages (a dry area would be more interesting for stockpiling food or having a...
Hey maybe on a tinyer level you could include some commensalist species which live in a symbiotic way with ants, such as Cyphoderus albinus. Those species could give a bonus to the colony if they decide to settle in, or they could appear in the tech tree as an improvement.