TUB.... Clearly the winner, well at least in my book. That price point it better have a tub, whirl pool... even better. Get some lavender and through it in and perhaps they will forget the closet is smaller . There are creative ways to get more closet space.
Whirlpool, regular, no difference except for being fancy but it has to have a tub. I would personally never remove a tub from a house if I wanted to resell it. Storage space is nice, but you can always add more closets outside of the bathroom.
On second thought, Over a half million$$$ It better have the whirlpool. It is to expensive not to. Even a $60k doublewide has a whirlpool tub in it.
In that price point I would leave the bath as is and look into a closet system for their average walk in closet space. This would create more utility for storage and uniformity while beautifying the space simultaneously. This should also add value when they decide to market their home with you.