On Topic
I think pitch recognition is an issue, albeit one that I think Rizzo can handle adjusting to. He made an adjustment at the start of the year and the pitcher's seemed to have adjusted to his adjustment, which is usually how it goes.
Off topic
Comparing a player to elite talent is irresponsible when it comes to talent evaluation. By your logic you would've written off a lot of players as they struggled to adjust early in their careers.
http://www.baseball-reference.com/players/y/yountro01.shtml
The game isn't as easy as Trout and Machado make it seem. I've never seen Rizzo as an elite talent, merely one who at the peak can provide .270/.350/.500 give or take. That'll play at first, and I still have faith that he will get there.