Alright let's see if we can put this to bed. There's nothing at all wrong or amateurish with your home. Agree seeing photo it's arguably too much of a compromise nor cost effective to move/change the window considering outcomes. The solution here will come in the fit-out and how to balance that as best as possible within the constraints set. You can do it with a 1500 size bath option, 900x1200 shower. and it's essentially a tweak/fine-tune from the idea you had originally. (I shouldn't really do this but here you go/I'm feeling generous today ;) ) You run a ledge all the way around the back and end walls. Mirrored cabinets all along the end above the basin. This will feel massive and luxurious with the ledges/more dimension & interest. But you'd need a concealed in wall cistern. Any privacy concerns (in bathrooms) can be managed by combination blinds/furnishings - arguably much more flexible (and cheaper in this situation) than changing glazing to frosted glass. And then you still retain an outlook/light to your ensuite during the day etc... Good luck & Merry Christmas :) PD

there's not enough space to have any open shower the best option is the sliding glass doors but a shallow bench with semi recessed handbasin and mirror doored wall cabinets would feel more spacious than a vanity

how many extra bedrooms do you need and what rooms will be downstairs and keep in mind that the stairs uses lots of space on both levels?...is a second story the only option?? .we need to see the original downstairs and a site plan to make any suggestions ?

Swapping the shower with vanity would still look good. You could have an opaque shower screen. Also with the current layout the shower recess would be reflected in the vanity mirror anyway. This would also keep the wet area on one side, bath and shower, and the dry areas on the other, toilet and vanity. The only negative is that the toilet looks private with the current layout and shower wall. Moving the vanity may make the toilet less private.