This has been an extremely complicated situation from the start, and I'm still not sure Saban is getting enough credit for managing it as well as he did. I think it is important to frame it properly. Nick Saban had a roster with only 3 scholarship quarterbacks (I believe he had other targets, and probably didn't plan on all his depth transferring), all teenagers, only one having played in a college game before. Considering 8 of his years at Alabama, he started either a fourth year junior or fifth year senior, he was dealing with a lot of youth and inexperience at the position. On top of that, his offensive coordinator left at a point where everyone else had been hired already. So, Saban had to just grab what ever OC he could and in this case it was a guy with only a basic grasp of the college game. So, you have teenagers and the guy coaching them basically knows nothing about coaching teenagers.
While prefacing this by saying I was wrong, my line of thinking all along was just snag a grad transfer or something and in doing so you not only save a year of Tua's eligibility, but you save yourself some drama (and believe you me, there was drama, which I think contributed to Hurts downward spiral). This was the safe play all along, you save the QB battle for the next year, you know your QB can get you to the championship game, so you take the easy way out. The problem of course was, what if Hurts hasn't improved enough to lead Alabama to a championship? What then?
The answer still isn't as easy as some make it out to be. First off, clearly Jalen Hurts was more prepared to run the Alabama offense at A-Day. Tua showed his skills, showed he was better at some things, but Hurts was demonstrably better with the first team offense. This is nothing against Tua, the guy was a true freshman after all. But, objectively after watching Tua and Hurts with the first team, even people like B1G readily admitted Hurts was the guy at that point.
The thing is Hurts mastery over the offense was still better in the early part of the season as well. In the CSU game, Tua was having so much trouble moving the ball that they had to pull him and put in Hurts just to put the game away. I'm not just talking about his .8 QBR either, the entire offense, running game included was out of sorts with Tua in. Once again, not blaming him, he's a true freshman in his second game. But clearly there were some things he still needed to master before he could run the offense well.
Now, apparently earlier in the season, before the Clemson game, Tua was thinking of transferring due to lack of playing time (though he did play liberally as a backup, so that translates to not starting). There's solid evidence that from A-Day to CSU, clearly Hurts was the guy that deserved to start because he simply ran the offense better (yes, Tua was more talented but there's a lot more to the position than talent). The problem is figuring out at what point Tua really did overtake Hurts, and at what point the reward outweighed the risk.
Saban saw more of Tua than any of us have. Some people talk like he's some old man that can't see what's in front of his eyes. Of course he did. But he saw more than we did. Remember, he's the one that decided not to redshirt Tua. He's the one that recruited Tua. He's the one that tried to play Tua early and often (I think Tua played more than any backup QB in recent memory). It wasn't like he did not value Tua's abilities, but he's dealing with a teenager here. One that's learning the offense, as Saban said struggling a bit with turning the ball over, and on top of that, as we now know, thinking about leaving. That's all understandable, but it doesn't paint a picture of a kid that has everything completely under control, he was like most kids would be in his situation, unhappy, and apparently a bit erratic with his judgement calls.
At the end of the day, Saban managed to steer Alabama to the championship game, win the championship game, and thus far keep around two quarterbacks who have threatened to transfer. To those that think this entire thing threatened his legacy, how he handles this is all about who he is and what his legacy is. He makes the tough choices, and for those that think he couldn't deal with the consequences? C'mon, he inherited a mess in 2007, he was competing for a title by 2008 and won a title in 2009. All of that with recruiting classes that had an average ranking lower than last year's criticized class. These guys need Saban more than Saban needs them.