I thought to this eventuality, but having a/the walls dynamical and not static is on quality level way too lower (in my opinion) than static walls, and working on visibility would not even permit me to work with “light as if static” option turned on; however the bigger problem would be faking the shadows: let imagine I have a lamp near the wall, I’d have to draw a silhouette of it on the wall in a correct way/position/blur/ecc, but at the first time a client ask a change on forniture type/position I’d have to redraw the silhouette, and knowing how many changes my clients ask at every project I’ll soon become an host for a psychiatric hospital! 
I feared so! ^^’