Transfer can be OP in endgames where only short-mid range pieces and promoters exist. It also can serve as a fork device when swapping appropiate units (Phalanx would be op if it could be swapped by this piece). The trebuchet needs some kind of buff, maybe eliminating the "Pay 2" cost would make it more viable, making oponent lose tempo for free
Yeah I'm not sure why meteor is pay 2.
firemeteormage needs a buff.