Nobody will ever know because what happened can't be undone but I am a big believer that had Sefo been given the opportunity to develop like he should have we would see a different QB now.
Not only was he thrown in early but he was thrown into a terrible situation with his team constantly behind, limited offensive talent around him, and a joke of an offensive line.
Habits are much easier to form than to change. Sefo quickly developed some bad habits while in survival mode that haunt him now. He doesn't slow down his mind and go through the reads, he tends to look to escape even when there is nothing to escape from. This all came from the conditioning of getting blasted play after play as a true freshman QB.
We constantly (with reason) complain about him locking on to a receiver and not going to the second or third option. We complain about him hesitating and going to a guy who is covered. From what the coaches say if you put him in a film room the can tell you all the reads and identify when he should go to the second or third option, when he should hold the ball a count more to let something develop, when he should just put the ball into the third row and run another play, etc. All the things that an accomplished QB knows how to do.
What we see on the field are the instincts and habits of a guy who never had a chance to let the game slow down enough for him to use his knowledge. We see the same mistakes as we did in year one because they are now habit. I would argue that given a year to practice and watch, maybe given another year as a back-up with a few opportunities to go out there and see some things then come back to film and practice and process them with the coaches, that Sefo may have developed a different set of habits, of football instincts.
Still not saying he would have been a great QB, he has some other limitations as well and still may have developed some bad habits but I will argue that he would have been a different, better QB at this stage of his career.