or maybe that it takes years to learn and on a major league team with playoff aspirations may not be the best time
That's not why it is for me - I'm not sure the learning curve for RF is that much less than it is for CF - Lombo, Soriano, Morse, Harper, Espinosa and lots of others sort of show that if you're talented enough at baseball to play at the MLB level, you can generally handle a position switch with relative ease - maybe you won't be a gold glover, but you can at least fight it to a draw.
To me, the thing that worries me about Harper as a long-term CF option is the increased likelihood of injury - you do a lot more running in CF than you do in the corners - you dive more too and have responsibility to get to more balls. That's extra wear and tear on the body. Besides that, it's totally possible that he's got some more growing to do physically - if he gets much bigger, he may be better suited to a corner.
In some senses, it's almost sad that his arm is as good as it is - I'd love to see him with a 1b mitt, but it would be wasting both his speed now and his arm.
By the way, my mancrush quote of the day is this:
“I think I have another level, absolutely,” Harper said. “I’m not hitting .300. I’m not doing what Trout’s doing. Trout’s hitting .350, .360, so he’s blowing my numbers away.
I love that he's looking at Trout and thinking "I can do that or better." He also very quickly followed that up with the right "Just happy to help the team win," point, so it's not like he was me-focused. Great ballplayer. Solid citizen.
EDIT: I have JCA on ignore.