Great built-in closet. In new house, used this to inspire. Since 9' ceilings moved each hanging shelf up 6" and added another storage shelf on top. Moved the pull out shoe shelves to far left by the entry and put wheels on the lower cabinet drawers. Since walk in closet have this storage on both sides with a 6 drawer tall dresser at end.
Pull out Wardrobe Rail for under stairs. You could have a few of these attached under the higher stairs and some storage boxes or even a chest of drawers underneath, then you could do away with the black frame and the room would look / be much larger.