Off topic, but you started it (sorta).
I remember seeing a special (a long one too) on ESPN a few years ago. Apparently Florida had brought in a QB specialist just to improve Tebow's throwing motion (after his Frosh. year, I think), and broke it down, and rebuilt it and changed it completely.
According to that special, he did have someone...
Muscle memory can be changed. No doubt about it. I taught myself how to play the guitar, but when I took lessons I had to re-learn how to do it. There were plenty of things I was doing wrong. You can fix things, it just takes a lot of time and reps to get it right. That doesn't mean you can teach someone to throw on a rope, but you can teach proper footwork, selling the playaction, holding the ball and releasing it.
It's not about practice, but about practicing with purpose and intent. All of the practice in the world doesn't help if you are doing it wrong even once, imo. Quality over quantity, but to be an NFL QB you also need the quantity (especially if you are trying to improve accuracy). It can be done, but it's hard to throw 300 times a day as that puts a serious strain on your shoulder, back and especially your rotator cuffs.
I saw something interesting about Eli and Peyton a while back. They all (Archie's sons) wanted to be QBs. Guess who was their teacher? While some say genetic lines matter--and they do--no one studies and practices like Peyton at his position. Anyway, in the interview they said they didn't go very much on vacation or have much of a social life growing up because they wanted to be QBs and they practiced
every day. Everything they did wrong though early on was caught by their dad. It wouldn't shock me if Peyton has a son in 15-20 years that is an NFL caliber QB. Over the course of his life he has probably thrown 100s of thousands of passes. That's a **** ton of work over the years. Mozart's father was also considered to be the best music/piano instructor in Europe at the time. It's no surprise that either of them had the advantages of having the best instructor at such a young age and they were "prodigies."
While guys like Elway and Marino and (insert incredible QB) may not have had an NFL QB dad I'm sure their parents got them the instructor they needed early on or they lucked out and had a brilliant HS QB coach (when it really matters) and a good QB coach in college.
I guess what I'm saying is that Tebow didn't have this early enough and Meyer let him skate by at his time in Florida. He has the work ethic, but he is a project. In a few years he might be good to great or he may never pan out, but he'll be better than he is today.
I *LOVE* the fact that Dorman had a grandpa that taught him, and his 2 NFL QB sons, and he had 2 talented uncles that could also help him practice perfectly. He's had proper instruction since he was little. That doesn't mean they are perfect, but I bet he's better off than a lot of other QBs out there. IMO, this is the steal of the class. Dorman has the physical tangibles to be an elite QB and the years of practice under his belt to do it. Can't wait him to see fight for PT. Having an NFL caliber QB coach is going to do this kid wonders.
EDIT: I'm not a Tebow defender--not even a Broncos fan--but if Tiger Woods can change his golf swing twice then Tebow can change his throwing motion. Thing is, is that Woods is known as a guy that practices 6-8 hours a day with his craft. If Tebow does that even in the offseason I think he'll have a chance.