Why am I experiencing listener's fatigue?

Vertigo, that would be waaaay too much toe-in for me. Try aiming your speakers at a point behind the listening position that is equal to the distance from the listening position to the speakers (7 feet behind the listener, in your case). If there is enough room between the side walls and your speakers that first reflection aren't a problem, I would try aiming them at a distance twice that far behind the listening position. I realize toe-in is really subjective and depends on room, speaker, gear, etc., but that amount of toe-in would drive me insane...not to mention that pointing the speakers directly at the listener's ear destroys soundstaging in a very substantial way. Try changing the toe-in combined with using something handy like towels or rugs for taming first reflection points and see how it sounds. At least it's easy and cheap! Hope that helps.