Hanging a room is editing in space. These are the rules I work from, in the order I usually abandon them.
The last one is the one I never break. A label can tell you what you are looking at; it cannot make you look. If the work has not done that job by the time a visitor's eyes reach the wall text, no amount of writing will rescue it — and I write the wall text, so I would know.
Leaving a wall empty is the hardest of these to defend to anyone paying for the room. It is also the one visitors remember.