Yes! Maybe, instead of deleting a room, we could 'Demolish' it - for a price, of course. Also, it could be interesting if we could upgrade rooms like we do in Fallout Shelter, for example. Upgraded rooms could increase production/training/styling/whatever speed and quality.
Upgrading rooms is a nice idea, but it would at least double the art required for the rooms, won't it? Or perhaps a simple roman numeral on the corner to differentiate different upgrade levels.
Yeah, giving all rooms new art for their updated versions would be a pain in the butt. Maybe just add the upgrade lvl. to the tooltip when you hover with your mouse, along with the upgrade's effects.