You could create an ensuite by borrowing space from the second bedroom, accessing it from the master. I would create one large luxury family bathroom by joining the current bathroom and the adjoining room into one. If you don't want to lose a room, you could swap the purpose of the two rooms, creating a medium sized bathroom and a small box room/study (expensive for some benefit). Lastly, if you really want to maintain the number of rooms but gain a bigger bathroom, you could move the family bathroom to the bottom, right-hand room, if plumbing allows. Hope this helps.