Statistically I understand this comment, but Campbell and Arias are not the same.
Even when Campbell was lighteing up AA/AAA there were questions about a hole in his swing, where's Arias makes better contact.
Also, Campbells long term defensive home was in question where's Arias is an elite defender at SS. He's going to get more rope in the majors because he can play a premium position well.
I'm all for waiting on him for next year, not rushing him, and nothing is a sure shot, any prospect including Arias can fail but he seems like a safer bet than Campbell was.
Campbell.........might still be a MLBer one day.