What about using the toilet and then having to open the door (grab the door handle) and walk over to the sink to wash your hands?
That's how bathrooms (in people's houses) in England are. I don't like having the sink in a separate room from the toilet. But it does free the sink up if someone's using the loo.
What if you are sharing with a friend and you don't want to know each other that
I would hope there is at least a curtain in front of the shower door to give both parties some privacy. Otherwise you could hang a towel over the shower door.
Overall, I think it's better to have toilet, sink, and shower in one room all together. Is there at least a changing/drying area in the shower area?