This design is very cool, it has that fun loft look and feel but not so much a master bedroom feel. Spaces like this can be the best part of a house if designed correctly, with a few changes this could be a great master bedroom.
this would actually be a really fun idea to bring light into the space. a ladder could go against the wall where the metal desk is now with string lights. it would be nice to see walking into the room from the hallway