It fits actually. While I agree with your take he shouldn't be nervous after being QB1 all last season, I'd guess Fall Camp was no contact for QBs. Couple that with an OL that hasn't gelled yet on pass pro in particular, and I could see some potential for live bullets "rust" in game 1. I was particularly interested to see how the OL would handle stunts/blitzes and creative lineups this game since they didn't handle it so well last season. I think once they "know" what they're supposed to do, then that talent will be able to assert itself with authority. Question is, how soon can they get it together. Likewise with Ewers.
Keep in mind that the OL practices against a particular defense and probably get's to know their tendencies. Rice wasn't obligated to play by that script. They don't have to be superior talent to generate confusion in the OL.
Ewers' first half poise was shit and he took sacks he shouldn't have. Hell, he self-sacked once. 995'rs pumped his improved footwork, haircut, mature approach, faster release, deep ball connections and going through his progressions. I think he failed under live fire and reverted to poor habits. But he just might adjust and be better in game 2. He'd best get it together soon though or make way for next man up.