The fact that the front door opens into the kitchen has always bothered me too, as well as all the other problems that BlackPearl mentions. One would think that Playmobil would put a bit more thought into the design of the house.
To be historically accurate, I'd like to see a basement which could contain the kitchen and servants' dining room. The ground floor would contain the parlor, dining room, and study, and the floor above that would contain two bedrooms and a bathroom. The attic could be for storage and the servants quarters. And the staircases with railings on each floor would be standard.