The only reason to name the coach before the end of the regular season is to satisfy the impatience of the Husker fan base. In the long run, it won't matter one bit if Rhule or some other coach is named Monday between Wisconsin and Iowa or the Sunday after Iowa. The next coach will be successful or not on his own time.
If the new head coach is named before the Iowa game, then he may show up to the game and be interviewed for about 5 minutes during one drive of the game. Mike Riley made a short appearance during the Holiday Bowl after he was hired. Riley also appeared on that coach's broadcast on ESPN during the National Championship game, and NU fans nearly creamed themselves thinking he was so good on there. Did those appearances have any impact during Riley's tenure at NU? Did Scott Frost coaching UCF in the Peach Bowl after he was hired, where NU fans were thinking "It will be a 4 hour commercial for Frost taking over at NU" have a positive impact on NU?