1 big bath or 1+ 1/2 bath?

We are renovating our small bathroom (the only one on the 2nd floor, and no bath on 1st floor) and have the opportunity to either a) put in a larger tub b) put in a double sink or c) steal some space from a walk-in closet on the other side to give the master bedroom a 1/2 bath, either sink+toilet or a shower. Right now the only other bathroom in our brownstone is a crappy half bath in the English basement, which we hope to one day renovate into a luxurious full bath. Since right now it’s only my husband and me, I am leaning towards simply expanding the bath we have, adding a double sink to accommodate our morning routines. But I realize that my husband and I most likely will move out of New York in a few years’ time, so I am considering which reno might be most appealing to future buyers. If you were buying a home, would you appreciate a 1/2 bath in the master (in which case, sink+toilet or shower?), or would you rather have a more spacious primary bath? Many thanks for any comments.