I'd love to have an open loft. Just keep the stairs flush to the wall this time, the little nook in the medium houses is nigh impossible to work with.
It just sounds like a mansion is too much house for you personally maybe you should downgrade to something smaller.
Either way might be a pipe dream, I believe recently Yoshi stated they aren't going to do anything more with apartments and opted for more wards instead. Probably for the best as few people are content with owning an apartment over a house.