I't would be easier to assemble a balanced group that said "tank" instead of "warior", itens shoud affect bolth (to keep the same item worth)
Also, maybe dayly reward for those who log in frequently? not talking about gems (maybe) but like 1M gold or 1 formation? 1 common monster but then it becomes rare, epic and so on with more and more days in a streak?
 "Idle Monster Frontier"){kind=icon}