In reply to:
There is some fact in placement away from back/side walls improve the overall experience, but it is not required for you to aim the sub right at the listening area.
The biggest effect is definitely placement against a wall or two (corner). If a sub has enough power, it should be away from the walls to make it easier to "dial in". This has the unfortunate effect of reducing the WAF. A smaller sub placed against a wall or in a corner benefits from the "extra energy" produced from reflections. I believe this can make it more difficult to sound good and may require strategically placed bass traps.
You are correct in your statement of not requireing to aim the sub.
