If by "almost everybody" you mean everyone except for:
- their leading receiver (Hemingway) and another key receiver and returner (Odoms)
- one of the best centers in college football (Molk), and another starting o-lineman (Huyge)
- their best defensive player (Martin), and another key defensive lineman (Van Bergen), as well as a key LB (Herron) and a key CB (Woolfork)
- a very good starting TE (Koger)
then, yeah, they bring almost everybody back.
Don't kid yourself--that 10-2 record was more a product of an easy schedule (getting OSU, ND, Nebraska all at home, while missing entirely Wisconsin and Penn State) than anything else.
Next year, the schedule isn't nearly so kind--although they still luck out and avoid PSU and Wisconsin, they have to go to Ohio State, ND and Nebraska, and play Alabama in week 1.
Even if you're right and they're a top 5 team headed into the season, that'll all end after week 1
when Alabama blasts them by 30+.