From what your describing we had the same thing going on,I didn't like the ensuite( too small) and the bathroom needed to be bigger,so we got rid of the ensuite and put a door between our bedroom and bathroom like a jack and Jill.After a while I felt it just didn't work so we closed up the wall and we now have one big bathroom.im glad we did it now. I too wondered if it would devalue the house and I'm sure if a larger family moved in it could be a bit of a problem,maybe someone from the real estate world will pop in and give you some advice. Good luck with whatever way you choose to go.

Hi. I'm a bit confused, have you bought the vanity and are looking to paint it? Is the rest of the bathroom fitted as you could add brass or copper taps for instance with a matching mirror? Accessories will also warm it. I like a little wooden stool in a bathroom which you can add accessories to i.e. A candle, natural sponge, flannel etc which has some texture. A plant on the window sill if you have one and then nice accessories for the sink and either some coloured towels or I like hammam ones. I've found a couple of pics but they may not post as houzz has issues :( These are using deep rich colours which may bring the cabinet towards you a little. A darker top for the vanity would also work

I've been thinking about options to cover all basis and came up with this. To allow guests to use a bath/shower the ensuite would be shared. I added a wall in the master bedroom to divide it and add privacy so guests don't have to walk into the bedroom to get to the bath/shower. The upsides are that the ensuite is larger, includes a bath and shower and has more vanity room. Also, by diving the bedroom I can add sort of a walk-in wardrobe. The downsides are that there's only one bath/shower that has to be shared and guests have to walk through the walk-in wardrobe to get to it. Also, it reduces the size of the master bedroom but it's quite a long room anyway and it would cut out the light from the windows in the bedroom. Personally I don't see these as big problems but I guess some people won't like it. Do you think this is a good idea?

??? not sure what this is trying to show? a painted cabinet?