I either enjoy or wish I had
good plastic weather curtains
comfortable seats
lights for interior
seat belts
gas gauge
inexpensive add ons for clock, temperature and compass.
We LOVE having a four seater and a two seater so that when the family comes we can carry almost everyone. The last ones in get strapped to the roof.
Have not wanted or needed a fan or a heater. Like full size rather than some of the custom small carts with doors, especially if you play a lot of golf. Too crowded for two men generally.