Man I think the defensive sub rule needs re-worked.
Watching OU-Baylor, OU makes a sub, and lines up to play. Baylor walks on their sub, and walks off his replacement using the whole 25 second clock forcing OU to call a time out.
On the other side; I've seen Auburn get 2x touchdowns, different games, by the refs not holding up the play. I see the Defender sprinting to position and the Refs allow the Tigers hike the ball early and pass it to the wide open 11th man since the defense didn't get a chance to sub.