I think that if you really upgrade it, and make it a lot better than it was before, than this is a great option to consider. With that being said though, there is a possibility that it will be looked at as a 'downgrade' in the future. If you only have a walk-in shower, it won't be considered a full bathroom, and you may lose a bit on the sale. I think you really need to consider how long you'll be in this house. If you're going to be there for a while, you shouldn't focus too much on the resale, and do what you need to to make yourself as comfortable in that place as possible.