Seriously, who ever thinks Jackson and Willis are on the same level needs CAT scan. And trying to compare Willis last years number is laughable. If there is someone that benefited from the Tebow offense, it was the running game, specially WM. Look at most of his runs, he was going through huge holes. Had he had more speed, he would have had an even better year. Sure he was goitng agains 10 man fronts, but most of those men where zeroed in on Tebow. Look at the film, not the stats.
Sure you could say the are both bruising type backs, but the truth is that Jackson doesn't bruise. He punishes! We need that attitude in the offense. If Jackson is available and his demands are acceptable, go for it!