Up to date decor!
No more ugly window valances or pelmets, no more light-blocking side valances. No more brown shades. Just put in some normal curtains, cellular shades in a light color, or decent quality blinds.
No more super-ugly bedspreads. No one buys a house with a bedspread in it. People can pick their own bedding.
Go for some light-colored cabinets and neutral/light walls. Why make a small space even darker and smaller?
No more skylights, only a couple of vents. Just put in decent LED lighting.
Put the water pump in a location that someone besides a contortionist can access it.
No more carpet.
Put a 2 burner stovetop in smaller RVs. I have never used 3 burners at once, and they just take up too much space. Go with a more modern design, with sealed burners, too.
Either make a better oven, or don't put one.