Klipsch loudspeakers should be against a wall. Subwoofers should always be against a wall or in a corner. The problem is matching the subs to the main speakers in time. That requires DSP which most do not have.
Placing speakers against the wall doesn't not affect the 3rd dimension. Your brain can however. In humans what you see can affect what you hear. Always listen with your eyes closed. You will get a much better appreciation of how the system is performing.