what they could do is reduce the cost of the second building that unlocks the song and yuang dynasty, for example: you choose a distinctive building to go to castles that costs 600 and 1200, but the second building must cost less resources. The current cost doesn’t justify paying 1200 + 600 for the Imperial Placio buff and the Fire Lancer unit unlock (which was heavily nerfed). And it’s also not worth paying 2400 +1200 for the great wall and unlocking the grenadier, the grenadier is strong but equally expensive