Well, first and foremost I bet this is related to salary. The OC is going to make more money than the QB coach, so keeping the offensive coordinator title would likely keep Stinespring at his current pay rate. There are plenty of schools out there that have a "running game coordinator" and "passing game coordinator." Only one of them calls the plays. The title is completely related to how much they're going to make.
More VT staff intrigue is available for your reading pleasure at the above Gobbler Country link.
SB Nation's Virginia Tech blog, Gobbler Country, warns Hokies fans against jumping too joyfully at the news of Bryan Stinespring's demotion. Mike O'Cain, it turns out, is not a magic bullet:
While I'm sure there is a large segment of Hokie fans who are ecstatic over this news, I think the feeling we should have is cautious optimism. O'Cain doesn't exactly have a track record that is significantly better than Stinespring's.
In 2000, as North Carolina's offensive coordinator, the Tar Heels finished 58th in yards per game, 65th in yards per play and 66th in points per game. In 2004, as Clemson's offensive coordinator, the Tigers were 110th in yards per game, 109th in yards per play and 90th in points per game. His last team as head coach at NC State in 1999 finished 86th in yards per game and 96th in points per game.
Whether or not the offense will actually improve now that O'Cain is calling the plays remains to be seen. What is readily apparent is that the notion that Beamer is even resistant to change in his pursuit of a national title is completely out the window.
Bryan Stinespring Water Boy proponents rejoice, all 11 of you: The reviled Virginia Tech offensive coordinator has been demoted, and replaced in the position by quarterbacks coach Mike O'Cain. Stinespring will remain on staff in a position coach capacity, handling tight ends and offensive tackles. The news comes courtesy of VT beat writer Kyle Tucker's Twitter feed, and seems to have come as something of a surprise. (This isn't to say it's a bad surprise in all corners of Hokie fandom: Stinespring had a large swath of very vocal detractors in Blacksburg.)
On paper, the 2010 VT offense wasn't a disaster -- at least not beginning in Week 3, when the Hokies shook off back-to-back losses to Boise State and James Madison to rattle off 11 straight wins and gain a conference championship en route to the Orange Bowl. (Where, you'll recall, they were neatly dispatched by Stanford, 40-12). They ran the ball well in a unit that ranked 23rd nationally, behind the efforts of Darren Evans, Tyrod Taylor, David Wilson, and Ryan Williams, and boasted a passing offense that languished back at No. 72 thanks in large part to Taylor's adept feet. In terms of total offense, the team ranked 41st nationally, fifth in the ACC. Our Virginia Tech community, Gobbler Country, will have more updates on this staff development throughout the day; check back there and with this StoryStream for further news.