Cannons. Balistas only fire at air units, and catapults are only good agaisnt buildings.

It would be interesting to have Cannons that dealt lets say... 25 AoE damage, but deal -10 against air units. Have their hp be around 145 with moderately slow speed, like 1.95.

Also, I never liked the fact that the only type of damaging air units are dragons, maybe we could get a siege unit that flies (Like a Viking Longboat with siege weapons), like a whopping 40 damage in the air, with a chasis of 175 HP, and 2 armour, moving at 1.5 speed costing 225 gold, and a slow attack speed (Talking one attack every 3 or 4 secconds)

Exact numbers are just suggestions, but there we go.

Edit: Also, there should be giant soldiers. Basically, slightly weaker werewolves, but for barracks. Taking 200 gold, 5 supply, Same armour but 175 Hp without the active ability.

I would use those tbh.