Your sound-stage is cluttered because your speakers are way too close together at 4 feet apart and the images are overlapping each other like a pair of binoculars out of focus, and you never want the back wall distance of 2 feet and the side wall distance of 2 feet to be equal numbers.
Great tips so far, I would agree that your Speakers should be at least 7 feet apart and 2 feet from the right side wall if possible. I would also recommend moving the speakers out into the room approx. 3-4 feet as stated above, therefore you may have to move your listening position backwards in order to maintain your 8 foot listening position which is pretty good, if your speakers are 7 feet apart.
I would also recommend minimal to no toe-in in order to achieve a deeper soundstage. However, If you lose the center image with no toe-in (which is best tested with a solo vocal song) then you will either move the speakers closer together 1/2 inch each towards the center with no toe-in, or leave them where they are and try a very slight toe-in.
If your right speaker is any closer to the wall than 2 feet you may need an acoustic panel on the wall at the first reflection point in order to improve image focus. Keep in mind that you may need it anyway at 2 feet as well.
I would also make sure that you don't have anything in between the speakers unless they are far enough back behind the speakers.
You should also consider carpeting (if you don't have it), in between the speakers and the listening position in order to reduce the floor reflections and further tighten up the sound-stage.
I would hold off on the tilt for now and work on the above recommendations first.
Let us know how it goes, Good Luck!
Rich