I'm not sure how hard this would be to implement into the game but I think it would add some excitement.
What if we had a few buff items in the game that dragons really wanted. So you could be out zoning and if you are using this item there would be a chance of a dragon flying in and attacking your group. Maybe someone is using the wyrmslayer, dragon lance, humas, onyx shield, orbs, ect... and a dragon flies in randomly to attack group and take the item. If the group dies that dragon will fly back to its zone and they will have to go to that zone and kill the dragon to get the item that was taken..
But like I said I'm not sure how hard this would be but I like the idea of a little chaos with stacked eq groups...