Move the bathroom wall to the right side of the window to give you a much bigger master bath. Make the walk-in closet from this wall to the right wall. Your bedroom can then be from the existing wall where the bathroom door is all the way up to the top wall.
Hope this gives you some ideas.

So you can add windows in the bottom wall and you would take room from this bedroom to make a bigger closet and bathroom? Or is the second bedroom in play too? Or is there a possibility of added on? Not sure whats available?

also, this isnt just the master bath... it is the only bath for these two bedrooms?

I agree you need an architect. This kind of planning effects the entire house. For me to design your upstairs I would need a first floor plan, exterior elevation concepts, the buildng codes and any other restrictions.

hire an architect

Hi Resale,
If the entire floor is a suite, consider coming into the room from the landing. Put a window on the back wall directly across from the entrance for a wow factor if this fits in with the chimney. Build in a window seat underneath. If you have books, it's nice to have them flank this type of window. If not, consider another nice focal feature that draws you in. That could be lovely.

Bathroom: Move the bathroom wall to the end of that bottom wall window. Remove the door from the landing. Consider a wet room look to really update your master bath. Make a separate room for the toilet; nice to consider a small cabinet or built-in by the toilet for tissue. Build your WICs off your bathroom. Make sure to add a place for linens. I'm thinking an L shape; using the rest of the space to the right of the now elongated bathroom and the wall that now faces the bedroom. Leave a space to the left as a short "hallway" from your bedroom to the bath. Consider built in shelves or a nice art niche in hallway. Hallways can be a beautiful transition from room to room.

Bed placement should be against the right wall. Consider building an area around the bed that has a 1' dropped ceiling with a wide arched entrance (nook). This can give a large sleeping area a very cozy feel and it's unique. Think about your ceiling treatments. It can really change the feel of a room. Cottage? Use bead board. Traditional, old world? Wood beams. Contemporary? White box beams. Lots of options.

With wanting to go for a lighter look; paint in creams, wood floor if it fits the budget.

Good luck!