One thing that stuck out to me about Sims after he committed to GT was an interview he did. After watching his film in which he was very dynamic I expected a flashy personality. Instead he was very Nesbitt-like: direct, grounded, and unpretentious. I could tell he was a worker and very serious about his craft. I came away thinking this is a really solid, grounded individual.
This season I liked his mental make up. He made mistakes and/or had unfortunate things happen and for the most part he seemed to let them go and come right back out without letting emotions torpedo him.
I have no idea how good he will be, or how soon he will get there. It's a lot easier to learn to go through your progressions when you have time. It's a lot easier to step into your throws with time. IMO the cast of characters around him is going to get better, and that will help him get better. Saying he has a 60% chance of being better than Joe Hamilton (who was the best player in CF, sorry Ron Dayne) is unrealistic. Comparing him to generational talents (Howell, Lawerence) who lit things up their freshman years while surrounded by better casts of characters is unrealistic.
I think his running ability props up his floor as a QB significantly. Two things surprised me about him as a runner. First, he was WAY more physical as a tr-fr than I imagined. Second his vision and savy as a runner are really impressive. I knew he was elusive but when you add the physicality & vision….I mean the dude can flat out run the ball. He is going to drive some defenses insane running for first downs when everything is covered and he should be dead-to-rights. He also throws well on the run, keeps his eyes downfield, and is learning when to go for the completion v.s. living to fight another day. He has the ability to create on his own.
Passing I like his pocket presence although I'd like to see more sensing pressure and sliding/shuffling around in the pocket while staying square/keeping eyes downfield. Arm strength seems adequate for a P5 QB. His release is probably above average. He's had a lot of pressure on him this year so it's hard to see whether his accuracy could improve with more time and the development of better footwork. As others have said, recognizing defenses and going through progressions will have a lot to do with his ceiling as a passer, along with improving consistency, accuracy, and limiting of mistakes. Leadership and mental toughness are x-factors, but so far so good.
I see Sims having "a nice little career" at GT that most will be happy with. I do think he has a high ceiling that could be realized if he is able to develop and be consistent. So all in all I feel pretty good with what we have in him.