What if you could have an army at your base? (No Atlas)
You could equip them with weapons you buy / win in an event to attack the dragons with, same with armour, and they could be like the people who stand around your towers. The army could be situated on any island you want, but they take up a whole island - and you buy / win more people for your army. The weapons / armour / more people could be 100-500 lumber / meat. If anything cost rubies it would be 1-5. What do you think?