Leiwer playing at all is a symptom of the disease. I am not all that down on him, he is a non factor for the most part. His 2 catches for 13 yards isn't why we are not good.
The issue is that Frost wants to run a talent based offense with less talented players. If you play an offensive system like Iowa or Wisconsin, you can get away with less talented players, who work hard. With an offense that is most successful with fast WR and fast RB working in space, having the hard working, less talented players on the field just make your offense look slow and is much easier to defend. Frost has a soft spot for small town Nebraska kids and kids that are underdogs, he likes them better than some of the others and they are getting opportunities to play. In some cases, it is a detriment to the team's success.
JMHO