It's no secret that AOS Spock is less… restrained than his TOS counterpart. He's regularly more emotive, and there's even a scene in Beyond where he screams when McCoy removes the metal stabbing him. We've seen TOS Spock stoically bear the Deneva parasites with little more than a moan, so there certainly seems to be a discrepancy in the levels of control present. While some of this can be attributed to AOS Spock being younger and more traumatized, I believe there could be another aspect at play as well, that would stop him from ever having the control TOS Spock did.
To answer this question, we need to go back in time to the episode All Our Yesterdays. In this episode, Spock and McCoy are thrown thousands of years into the past, and Spock starts to go feral. This is explained as being because in this time period yet, Surak hasn't come around to get everyone on the logic train. However, McCoy doesn't go savage even though humanity isn't exactly civilized yet either, so what gives?
I believe (and I am not alone in this opinion) that the reason for this is Vulcan telepathy. While I don't think Vulcans have a proper hive mind, they may have… a general connectedness on a low level. After all, when the Intrepid was destroyed in The Immunity Syndrom Spock immediately knew what had happened even though he wasn't expecting anything to have gone wrong. He doesn't even seem to have personal connections to anyone on the Intrepid, and yet he was affected by their deaths anyway.
This could explain why Vulcan emotion is such a dangerous thing. Before Surak, when all Vulcans were crazy emotional, they would, effectively be hyping each other up. Not only do they have to deal with their own strong emotions, but the Vulcan 'hive mind' would be influencing them to be even crazier than they normally would have been.
This is also why being a bad Vulcan is so looked down on. If you're emotional, you're polluting the hive mind, and making it harder for everyone else to be at their logical best. If too many Vulcans became emotional, the collective consciousness as a whole could be tainted, and they could get dragged back into emotionalism.
In AOS, however, Vulcan was destroyed, and therefore the hive mind would have been, if not destroyed, then severely weakened. Vulcans wouldn't be able to fall back on the hive mind anymore, because there aren't enough of them to form a useful neet. Without that assistance, every Vulcan would be more emotional, including Spock.