I think at this point, as in RIGHT NOW, you're right. But Dak has shown he can throw the ball well. He'll be a force the next 2 years (unless he suffers the MSU QB curse his Sr. year).
I think another reality is that Russell is very average. I thought he'd eventually develop into a great passer, but he hasn't. He's a FULL level below Mettenberger and the others.