1) Change the color of the yards
Nobody wants to move into a plot that has dead grass in it. I get that you're going for a desert vibe, but (especially with the swimming update) the Goblet is clearly well irrigated. Having lush, green lawns would only serve to enhance the oasis feel of the Goblet, and make it feel more like the jewel of the desert it's supposed to be.
2) Unlock ward-specific exteriors
As many others have pointed out, the idea of the different housing wards each having their own sense of style went out the window the moment things like Carbuncle, Moogle and Shirogane exteriors were added. People who like the aesthetics of the houses in Lavender Beds might be more likely to move into open Goblet plots if they knew they could build their Glade houses there.
There's a lot more that could be done to improve the Goblet, but these fixes would be so quick and easy to implement that there's basically no reason not to.