[HoneyBadger]

One small thing that would really benefit Caelum in any age, without making them overly more powerful, is to equip some wingless troops with harpoons. That would give them a nice little boost, but at the same time, harpoons aren't going to win a game by themselves. They're also thematic, since any nation's going to want to possess the ability to strike at it's own people-and harpoons are the best choice vs flyers. Nets would also be good, as would a winged troop that simply dropped rocks on opponents.

Personally, if I were leading a nation of flyers, I'd just send them up to about 500 yards in the air with bags full of marble-sized to golfball-sized pebbles and have them drop them on any troops they happened to come across, but that's hard to simulate in the game.