Aliviti's listed size grabs a scout's attention right away. He's undersized. But at 6'0+, he's more than tall enough for the college game, and he has a skill set that has him play much bigger than his listed height and weight might suggest.
One reason why he plays bigger is simply because he's fearless. Sometimes discretion can be the better part of valor at the quarterback position, but Alviti doesn't play reckless. He plays fearless. He stands calmly in the pocket surveying all of his options downfield, and he'll run the ball between the tackles and fight for yardage in the trenches.
As a runner, his height, or lack thereof, is actually an advantage. He has a good center of gravity and doesn't expose himself to a lot of big hits in vulnerable areas.
Alviti has a good, not great, but good arm to make the necessary throws. He makes very quick reads and gets rid of the ball quickly.
He's not a prototype passer, but for a team looking to run a variation of a running/option spread, West Coast quick read passing game, Alviti may be the new prototype.
See him in action in this presentation by FOX Sports Next: