With regards to Wilbon-If he was good enough week in and week out to be on the field, he would have been. Whatever he isn't good at was significant enough for him not to play.
When he got in during the first two games he looked like a better runner than Newby to me and I know plenty that share the opinion. Then he just disappeared for the rest of the season. Unless there were disciplinary issues it is a failure on the coaches that they didn't find a way to use him.
First 2 games of the season Newby clearly had the better numbers
Newby - 6.3 yards/carry, 19 yards/reception
Wilbon - 3.9 yards/carry, 14 yards/reception