Okay, so starting with the first two screenshots:
The "scrunched down" affect that is seen here actually favors well for the widescreen in my opinion. The fullscreen shot looks "scrunched in" and gives the crocodile-like animal the appearance of having a short snout.
2nd pair of screenshots: The quality of both sucks here. But I, again, prefer the widescreen shot over the fullscreen shot. It gives a bit more depth to the landscape. The mountains in the widescreen shot look smaller, like if you were at a vantage point that made it appear smaller. The fullscreen shot makes it look to large, as if it were seen from a not so far distance which is not a bad thing, I just prefer the "the mountains look smaller because they are far away" shot.
3rd pair of screenshots: This one I'm not sure about. The Sharptooth looks a bit elongated in widescreen, but the same elongation causes for a nice looking background and foreground.
4th pair of screenshots: This one, fullscreen wins in my opinion. This is one of those times when the "scrunched down" affect just doesn't fit. It makes for a weird vantage point.
5th pair of screenshots: My favorite, and I give this one to widescreen. When I was watching this scene in "widescreen" (and scaled) I loved the feeling it evoked. The widescreen shot sort of gives a better look at just how big the Great Valley really is. The "scrunched down" affect is the downside. It is prominent here.
At some points in the movie, the "widescreen" made the viewing experience better, while at other times it wasn't as nice.