Marisa,
You can definitely tell you are a woman and a real estate agent. You would not have a job if it was not for architects and designers.......... we have everything to do with the resale of a house. you not sale what we build/design, wither it is new or old. Adding any thing to a house should be well thought through. I'm only giving my yrs in experience and hundreds of clients that I have met with (mostly women). My information is only a suggestion. As far as women loving tubs. I have a wife and 2 kids. In our previous house my wife only used 1 tub for our children and we used the other tub/shower as a shower only. My wife has never used the tub herself. She prefers to shower. So with that all said I still think it goes back to personal preference in what your wanting out of your bathroom. You are going to be living there, And a tub or shower, tub/shower combo, or a plain tub is not going to break the sale of your house. There are way more important factors to selling a house than a simple tub or shower in a room that only gets used by the people residng in the house.