Not if he's trying to make it into the national team. MLS is where fútbol stars go to retire (Messi, Beckham, Ibra, Villa, etc.). No one here takes the league seriously. The level of competition is extremely low.
Says you. The market determines a player's worth. It's however much a team is willing to pay. At the time, he was a rising star at Dortmund. We weren't the only team interested in him.
I think it's more based on how he's performed in the big matches, when the spotlight was the brightest. No one really cares how Ter Stegen performs against the minnows. He's choked in the big Champions League games, as of late anyway.