I think Mier is 1st on that list. 4 years and still hasn't played an inning above hi-A. He needs to be in Corpus this year and show that he's ready to finally earn that 1st round money.
Let's temper our expectations a bit. He'll likely never live up to the billing of being a first round pick and/or being drafted ahead of Mike Trout. If he can just put together a full season by which to evaluate him I'd be happy. Jio will be about average age (~22) for AA prospects but he hasn't shown anything hitting wise that suggests he'll a first division starter.