Your analysis is excellent. I personally think that Mark Sanchez may simply have been drafted too early; I think he could have benefited from the seasoning of another year in college. Another factor that has hampered his development is the fact that he's been injured multiple times since entering the league.
For the first half of the league, Sanchez was phenomenally efficient, no doubt aided by his running game. He was on pace to perhaps set a record for fewest passing attempts to 30 TDs. His production tapered off toward the end of the year, no doubt impeded by his injuries.
My main objection to all the accolades heaped on Mark Sanchez is that they seem to be based mainly off (a) his perceived potential as opposed to his actual production and (b) the fact his team made it to the playoffs his rookie year, even though statistically he didn't play a huge role in their success that year. (In fact, he was objectively
bad). I just wish assessments of player performances were more objective and weren't based so heavily on a single metric: wins.