Bath and toilet connection in one room
As for the shortcomings of such a combination of premises, it is only one single. Namely, the inability to visit two different for the purpose of the premises by two people at the same time.
Make such a redevelopment or not, solve only owners of their own apartments. If you are satisfied with such redevelopment of the premises, then forward! Embody your most bizarre and secret wishes into reality. And if this option does not suit you, then leave everything as it is.