From http://www.weather.com/glossary/w.html
WIND DIRECTION
The direction from which the wind is blowing. For example, an easterly wind is blowing from the east, not toward the east. It is reported with reference to true north, or 360 degrees on the compass, and expressed to the nearest 10 degrees, or to one of the 16 points of the compass (N, NE, WNW, etc.).
Therefore a wind of WNW is blowing
fromWNW. This, ironically, supports the debris field rather then refutes it.
What is missing on the diagram is the measured (via radar) flight path of Flight 93, so a huge bit of data is missing. As far as the engine being where it was, since we don't know the flight path, particularly at the end when it would be expected to be "uncontrolled", just pointing out the distance from impact does not add value because too many other factors are not known.
Back to the original post, it does not make a point.
As far as blowing debris 8 miles with a 10 mph wind, again what is missing is a lot of actual data. At what altitude was the debris released? What was the wind speed at that altitude? (The reported data is at ground level, and is not relevant to the debris.) What was the debris and what is its expected aerodynamic performance? (I.e. a rock is likely to be in ballistic free-fall, a magazine cover is not.)
What is the local geographic topology when overlaid on the above map? There was a statement about a mountain. Where is it on the picture? (Topo maps of the area can be obtained from http://www.dcnr.state.pa.us/topogeo/gismaps/topos.aspx by following the "Download digital raster graphics (DRGs) of Pennsylvania from PASDA" link. The specific file is ftp://www.pasda.psu.edu/pub/pasda/drg24k/stoystown_pa.zip and it contains a large tif file.)
Personally my theory is that the separate debris fields represent more than one missile that was fired at the plane to shoot it down. The first one did 'light' damage but left the airframe mostly intact. The second one left the plane out-of-control in a fatal dive and it "flung" an engine off as it was spiraling out of control.
(Lest one question whether or not a plane can fly with its skin compromised, recall the Air Aloha 737 that had the entire top of the plane peel off like a pop-top cat food can. It landed "safely", and when you look at the photos, it feels like a genuine miracle. The entire top of the plane is simply missing and the people are sitting out in the open.)