Bryce Harper's future is a 50 homer a year All-Star. If he grows any more, it may be best to move him to the corner outfield just to slightly reduce the wear and tear. He is a already a good CF. I think wherever he ends up in the out field he'll eventually win a Gold Glove.
And yes, I do think Bryce Harper will be the greatest player of all time, but that is for another thread.
I think you can keep him there for a couple of years, though, and let Goodwin, one of the other options coming up, or wait for a better FA option presents itself. I don't think there's a huge rush to move him to a corner.