I think you're being a little too hard on it. Sure, don't like Giggles if you wish, but I don't think anyone felt the sets were cheap. Asylum was a 3D house, it's always going to have a "cheap" look.
To epcyclopedia's point, most of the time, it's because things change close to the last minute. Whether it be the IP holder wants changes or didn't approve something (Scream, AWiL in 22) or Universal steps in (HoH in 22).