People say this, but we've seen the last 2 years that Day wants and needs to run the ball to dictate the game and set up shots downfield. Clemson last year was his ideal game. Hand the ball off to a RB with great vision 25-30 times and then take the top off the D.
OSU just doesn't have a great run game this year. It works against good not great defenses and they fall back to RPOs, bubble screens, and quick relief passes to make up for the weakness of the run blocking.
Now that they've established a precise passing game, we'll see how the O evolves next year. I doubt we see 40+ passes because the focus in the offseason is going to be using your star RB and cadre of talented backups to wear down teams. If they don't I'll be disappointed. No reason a guy like Henderson shouldn't be the engine for your offense.