Again, the Tebow comparison is hilariously bad. While Tebow did have problems fitting his skill set into an NFL game, he also had totally broken mechanics and did not have half the arm talent of Johnny Manziel. I'm still wondering why McDaniels took a chance on him, although I suspect it was because he was the dream player for a coach, if he was even marginal.
Going back to Manziel, I don't think many doubt his mechanics, at least not nearly to the amount of Tebow. His release is already very fast when he decides to throw the ball. In the Buffalo game, he stayed on balance, threw off the front foot, and was really doing a great job of footwork inside the pocket. He had some hiccups in his drop back, but that's going to happen from time to time with a rookie.
Manziel, unlike a lot of busts like Vince Young, Tebow, or any other highly overrated QB, does have the basis to be a successful pocket QB physically. He can do it, and he has shown to be a quick learner already when it comes to mechanics. The rest is all mental, which is also the hardest part of the game and the part that he didn't show vast aptitude in college. But, to be fair to both sides, he was not asked to diagnose a very confusing defense, nor was he asked to run a more pro style offense. He hardly ever had to turn his back to a defense. He did have to make reads, but it's not even close to the same thing.
Seeing him for a full game will give us a good idea of what he has learned and how he is progressing in the offense. While their are some VERY hard parts to the WCO, the Shanahan version can be dumbed down to a one read offense. Bring in more blockers, run less routes, and let Johnny make a play, it's the same formula that they did in Washington with RGIII. But I think Shanahan could push Johnny more than RGIII, mainly because the owner won't fire him if he does challenge Johnny and Johnny doesn't like it.
I'm excited to see him, we are getting a first look at our shiny new car.