Not really getting how you hold Altair to this kind of standard and seem to be implying that the other protagonist in the series are superior in any fashion.
I hate Connor for the same reason I hate Altair, the lack of emotion and dry personalities. The whole series is badly written, but at least Ezio has an interesting personality. I never said any of their progressions were good.
Altair had nuance to his dialogue that changed through out the game. He had very specific conversations that you were unable to miss or bypass where they go into his reticence to use other assassins in a job after getting a fellow brother maimed... all the while they are explaining to him that his past mistakes have fashioned his current station and rank - but he can't simply shut everything/one out and do the whole thing alone. That the assassin order was never meant to work that way. That the fight transends nations and races and peoples and is actually a war of ideals.
He DIRECTLY influences these ideals - in the first game even - to a great degree. He sees what absolute power does and gets straight PISSED at his former master.
He speaks in hushed calming tones to victimes later in the game. Understanding that they are all human even if they are a link in a chain that must be broken.
The problem is that it is through a bunch of conversations that makes it such piss progression. We are not shown through action how he changes. You talk about how he learns how he can't shove people away and do the whole thing alone, but for pretty much the whole game he is working alone. Yet some how his entire view point change from just conversations, but he still goes on doing everything alone. Nothing shows how he progressed. I never see him working together with the other assassins, he collects intelligence by himself and he assassinates targets by him self.
Again - ALL of this is more subtle, more depth and more intriguing (to me) than MOST of Ezio's/Connor's progression. Ezio who starts a big dick swinging normal dude and then becomes an assassin easy peasy... and proceeds to be that guy until he is fucking 67. And Connor.. who is so bland and vanilla that he literally just takes up the cause of whoever the fuck is standing closest to him with the largest personality at the time.
While both of their personal drive consists of "Ya'll kill my mom and pa."
And for all I know Altair became and assassin easy peasy because I never shown otherwise. At least with Ezio I have a reason to care. I have zero reason to go after targets other then the head guy said so.
Altair was always going to be an assassin. Mother and father both were assassins.. he was groomed for it young.. grew up with the skills.. became complacent and arrogant in his knowledge of said skills and was brought low for ignoring the core values of his brotherhood. That alone is a better story than 99% of the other games.
Except we don't see how he is brought low. Nothing in the game shows how he struggles at all, he does things so easily that it feels like nothing has happened to him.