I think that is an adjustment to the speed of the game vs college or the practice field. What they need to hammer into him is that when the season starts the speed steps up again and he won't see second or third stringers much. He has three more pre-season games to show that he can take better angles. I do not agree with the poster who said a few great plays can negate a few bad ones. In some postions that is true, but the safety position is called that for a reason. If somebody in front of him gambles and misses, he is there to prevent a TD. If he gambles and misses, there is nobody behind him and it usually results in points for the other team. It would be nice to have a safety make 6 or 7 interceptions in a season, but not if it is a result of gambling that also allowed 10-12 touchdowns. Not a good trade-off. A safety has to see the field, read the play, take good angles and be a good tackler. If he does that, he is doing well, and interceptions are just an added bonus.
Wilcox is an aggressive player and a hitter. I see pro-bowl potential, but right now he is just not ready to start. Maybe by mid-season. Remember that Darren Woodson was a backup and a special teams player when the Cowboys beat the Bills in the Superbowl. Wilcox is where he was in his rookie year.