He will definitely 'come around'. This is not Ryan Zimmerman's ceiling we're seeing.
However, he's never going to be a superstar that people think or thought he would be. He's not. That's not who he is. He's a 3B who will be productive to the tune of 20 HR/80 RBI/.280 when he's going well and an elite defender at third. A team leader. I don't think he's necessarily in the right role casted as a three hole hitter either. He is more like a five.
Tamper your expectations. Don't expect the world. He's maybe got a .300 season or so in him still but he is not a perennial stud offensive player by any means. He's just not. Same thing with a guy who went a few slots after him in his draft class Jay Bruce.