I do believe that the current upgrade costs for buildings is way to high. I do, ofc, refer to the coin based lines of upgrade. Compared to the wood/marble upgrades then upgrading a coin building costs 17 times as much as one upgraded by wood. Current price of 120 Hardwood is, approximately, 6g...this will upgrade the building, whereas the coin based upgrade is 100g for level 1 to 2. This desperately needs addressing, as lower level players would find obtaining multiples of 100g very difficult to come by.