You can use the "egg carton" foam or some other unsightly material behind them to add value.
When I pull my wool lululemon hat over my ears I notice mids are much flatter than others.
Wool Blankets as Room treatment
Just noticed Pendelton has some really nice wool blankets that can be hung on the wall. They even sell the fixturing. I would assume the wool blanked would have some beneficial properties for a blank wall?