This is what it looks like if the building was isometric.
I don't think it suits, because this picture has layers, where as an isometric piece is generally a flat, consistant image.

Here is my new version with pistachio's edit taken into heavy consideration

. It seems like no one likes the moon, but I still at least want it yellow, so I've reduced the saturation and also added some shading to make it look less like a flat pancake.
I know the perspective of the shadows on the objects on the roof are differet to the building angle, but I think they line up with the moon correctly.
The clouds now look like actual clouds too.
