Certainly, the best room would be one with clear wall space from the corners, adjacent room boundaries would be rigid and opposing boundaries would be perfectly reflection-free, either open space or fully absorbent. Obviously, this is not the case. The adjacent boundaries aren't fully rigid, nor are the opposing boundaries absorbent. But I've found that homes with a concrete slab and framed drywall construction provide a good environment for cornerhorns. The drywall is lossy, and it and the insulation behind it tends to damp the room. That's probably the single biggest thing in small rooms, you really need this damping from walls that have some give. This damping smoothes room modes, making bass more uniform.