Maybe last year was a long fluke and he figured out how to play QB during the off season. Who knows. But if he is the starter and hasn’t made miraculous progress we will lose around 2/3’s of the games he plays in. Likely would start 1-3 and I imagine after that they would move on to someone else but if they didn’t for some reason and he plays all 12 I’d say the ceiling is 4 wins.
Last year he was the worst BYU QB over more than 50 years and the 3rd worst in all FBS (both minimum 100 passes). Of course he can improve but so can all the others and I would rather go with someone who has shown they can be effective vs P4 (GB), functional as an FBS QB (Hillstead, Bourguet) or get reps to the young guy mostly to get him ready for next year (Lugo) before I’d give JR the reins again.
Of course this is all IMO.