You're greatly underestimating how much impact the mental aspect of the game and the efficiency of a development program have on a young player. They are carefully devised and applied in a way that respects this delicate balance. There's a reason why teams do things the way they do. You're saying "Oh, it's not radical, oh, it won't take time away from other things"....then why haven't they done it? It's clear they will move him off the position. But this is a kid who came over from Cuba and is adjusting to life in the US and life as a professional baseball player. They will try to put the least amount of stuff on his plate possible.
Also, do you have any idea how much work goes into positioning/footwork on defense to prepare for the MLB level? Again, there's a reason why they handle development they way they handle it, and no amount of made-up scenarios is going to validate any sort of contention otherwise.