The smaller the sample the more you should assume that normal gravity is going to apply. Moises demolished AA, but he's been more good than great at AAA. And it's also only been 19 games at Iowa so it's not like he's running out ofthings to learn.
There's no need to be impatient, he'll likely be an MLB regular as a 21 year old early next year. He's tracking great, he's just pretty clearly not ready to step in and excel right now.