Those are fair points, although a lot of those things have been addressed (don't want to jinx anything about special teams, but....). Johnson has taken over the primary back spot and has done well. THe thing with Yant could be an issue where he does it all the time in practice, and then it shows up in a game that cost the team yards.
QB after AM leaves is something to be concerned, but Smothers has gotten some decent PT and looked ok for a freshman. As long as this defensive staff is in place, I'm not worried at all about them next year or going forward.