Haven't seen it mentioned so figured I'd post, Bill Connelly at SBNation released his annual returning production rankings for 2019 (it's one portion of the full S&P+ preseason rankings that come out next week). Could be a nice break from spinning our wheels on recruiting news.
If you're not aware, Returning Production attempts to gauge how much talent a team has coming back, but instead of the traditional number of starters returning it looks at percentage of stats returning, with each position weighted depending on how well each stat correlates with future success. Thus, a returning QB is worth more than any other position. One interesting effect is that returning production in the passing game correlates much more with success than in the running game, meaning bringing back your DBs, receivers, and QBs is worth more than linebackers and running backs, etc. That's just the broad strokes, there's a more full explanation in the article of course.
Cutting to the chase, we rank 11th in the country and 3rd in the power 5 in returning production, with 60% returning on offense and 96% on defense. That's good for 1st in the country in returning defensive production, 77th in offensive (although I'm fairly sure that's counting McClease as gone).
A lot more than this goes into having a good year, but at least we've got some mathematical basis for optimism.