There are no positives when losing one of the better players off the team's worst and thinnest positions. Bostick is sending a message.
Bostick, while not a good player by any means, is a likely starter on a Big Ten team at Iowa. Elsewhere...literally anywhere, including the MAC, he's a bench warmer, yet he's choosing to leave. That's what happens when Kirk lazily botches the hiring of the most important position coach on a college football team at OC...and opts to promote rather than fire Iowa's worst coach to WR coach.
This offense, led by America's worst QB last year, is going to be putrid. If you thought defenses loaded the box to stuff the run last year...wait til this year.