I googled just the teams in the Big Ten and SEC and 20 out of 28 teams have an OC/QB coach combination. Mizzou and Texas A&M have assistant coaches in charge of QB's, Minn and Penn State have passing game coordinators coach QB's, Michigan State has their recruiting coordinator coach QB's, South Carolina and Vandy have coaches fully focused on QB's, and Rutgers does not have a coach listed in charge or QB's.
A different sample yields similar results. Of the teams that finished in the BCS Top 25, three had dedicated QB coaches (FSU, MSU, South Carolina), Missouri's QB coach also held the Associate HC title which effectively brings the total to 4. Twenty had OC/Co-OCs coaching QBs, and one, Stanford, had one coach dividing time between QB, WR and RC duties.
So, in other words, having a dedicated quarterback coach really doesn't seem to have any kind of direct variation on quarterback play at all.
No it just doesn't make a difference at other schools but, with the top notch facilities and millions of resources at Nebraska it would change everything.