In this particular outing, Wells was solid, the double was a weakly hit pop-up the opposite way that happened to drop in the right spot (from the Astros perspective).
Regarding Willingham, the ball was a low line drive straight at him, the toughest kind of ball for an outfielder to judge, and clearly traveled a little farther that he thought it would, but once he knew it was too late to charge it and attempt to catch it, he kept his body in front of the ball in textbook fashion, especially since there was no way to read how much it would skid versus bounce on wet grass. Anybody who would criticize him for that needs to go back to Baseball 101. It may well have skipped right past Dunn to the wall.