There is incentives given to encourage us to invite friends to this game. However, after I and my friends joined the game, we found the possibility to interact with each other is minimal. Co op type of game is proven to be an essential contributor to a game's success. I really want to bring this up to developer's attention for the sake of making the game a better one to enjoy.
So a little bit of my co op ideas:
1. when entering quest in co op mode, instead of searching randomly, it should allow us to send invitation to friends who is online, and then the friend should be able to join with one of his army.
2. some dedicated co op quests that require strength of a few players to engage. For example, a siege game attacking powerful AI stronghold etc.
3. the PVP should also incorporate co op concept. For example, when being attacked, players could be allowed to send request to his friends for reinforcements.
Looking forward to seeing the game become a greater one..