It would be nice to be able to turn the shower on from the outside easily, which usually means the hinges are opposite the controls.

Is it possible to move the door? That would the optimal scenario. A pocket door could help as well, but it still couldn't go wall-to-wall. I've never had problems with sound/privacy with a pocket door. Maybe you could put the vanity towards the back part of the wall, then install some shallow shelves behind the door, so that space isn't empty. Might help balance it a bit. Or a nice, big, heated towel rack :)

Start by getting some LED lighting that does not heat up the space everytime the lights are on . Since it is an attic bathroom makes sure you have a good exhaust fan that is actually vented to the outside.Not sure what you want tochange but in such a small space all that dark wood is gobbling up light so I would paint it .A couple of towel hooks instead of all the towel bars would be good. How many people use this space? Decluttering the vanity space would be good. I can’t quite figure out the layout where the louvered doors are.

Congratulations on starting your project! Especially in the early days of a rehab, it is easy to get caught up in how many ideas and desires you have for the finished house. Be cautious and try to avoid spending too much time on elaborate schemes. This is the big chance for scope creep and before you know it, you are completely gutting the house.  I presume your objective is to first, finish the rehab and second, make a profit. Think about who will be your target market and why this house will appeal to them. What features are common in other houses in that market that you don't have? Or, is your house going to be a top choice simply because it has been updated. Don't price yourself out of your market with expensive choices your buyers can't afford.  From that perspective, I suggest you do a lovely large and open master bath. Skip the tub as it isn't going to make you any money. I would not have two sinks either. The way you have drawn it, you will need to buy two mirrors, two light fixtures, two sinks, two faucets, two vanities, and the associated plumbing for both. Those items will add several hundred dollars to the budget but won't sell the house for more money. It is OK to have a big bathroom with lots of floor space and not stuffed full of expensive plumbing.  Use a single vanity and have lots of counter space. If you can find an old dresser, buffet, server or credenza, you can make a nice vanity for much cheaper than buying new. You may find it cheaper to build a closet than buy a linen cabinet. If you have a ReStore with cabinets for sale, you may be able to find some you can use to build in storage. My upstairs master suite has cabinets built in the knee wall that were converted from an entertainment center. A single piece of cabinet grade plywood would cost more than I paid for three cabinets ready to modify for my space.  It is easy to make a space look fantastic with a cabinet topped with a custom corian countertop you can create and install yourself. When it comes to a flip house, the choices don't have to be the prettiest, just attractive and suitable for the purpose. For example, a used or clearance vanity light can save you $20 to $50. Another option is to frame out the shower with support for a door but leave it for the buyer to install or use a curtain.