The map is quite interesting, but does have some inaccuracies. For example, the Queen's Audience Chamber is not in the center of the north wing as shown, but is rather in the west wing facade overlooking the garden (2 rooms north of the White Drawing Room). That line pointing to the Audience Chamber is actually the King's Staircase.
In general I would say the palace layout does suit its purpose and use; the private rooms are mostly in the north wing, the State Rooms mostly in the west wing, guest rooms and offices in the east wing and service rooms in the south wing. But, I agree with Joan that improvements could be made.