You're right, he has a lively arm, stronger than many NFL greats.
He is indeed short but taller than several NFL greats. He's plenty smart and just athletic enough to learn, adapt, and find throwing lanes. His best talents are accuracy, finding the open man very quickly, and getting the ball out. Those talents are a little rarer than a cannon arm.
He's been called a "field general", which Payton called a "CEO". I don't know if that's deserved or not, but I have seen his smarts, and he's top-notch in that regard.
I have no idea if he will ever be a starter, just saying that he has some solid talents