I've found the buildings for Tokyo and London zones are affected by the wealth forecast. But I haven't noticed a difference in Paris ones. For example, there are max upgraded Tokyo towers that are more colourful if the zone is premium rather than luxurious. Some of the lower level London buildings are darker ... even to the point of drabness if it is not luxurious but it is still great to have for variety. I have a tiny premium zone now to upgrade those buildings then move them back to their final position since I focused on only luxurious before and missed out on some neat structures.
