Nice discussion. Agree with br that Jackson can't be K'ing like he did last year and make it. And as JR suggested, the magnitude of his K-problem and the fact that he's had a K-problem since he left HS suggests that his K- and contact-challenges probably go beyond some tiny mechanical adjustment.
But I also agree with Dave that mechanical adjustments can be made, and that BA wouldn't still have him as high as #5 if there weren't some scouts who think he's salvageable as a good enough hitter to start.
There is a huge world in between having no K/contact-problem and having the magnitude of problems that he had last year. With coaching, there's a chance that he can limit the damage, and if so he can become a good starting player. The 28% K-rate that Dave and tico mentions is still very high, but it's a lot more livable than what he showed last year. So lets hope.
I do always wonder, though, if you can have a win-win-win solution, or if there will be a price. Win-win-win would reduce the K's, but with no reduction in HR-rate or walk-rate. Perhaps that might be possible, and addressing the drifting or seeing-the-ball problems will benefit HR's and walks while also reducing the K's. But a lot of times the price of reducing K's is cutting back on the swing which results in less power, or swinging earlier in the count which results in less walks. So if adjustments that reduce the K-rate to 28% also reduce the walk and HR-rates by 20% each, a 28%-K Jackson won't be OBP'ing at .350 after all. But hopefully some adjustments will be win-win-win. Perhaps the HR rate will rise if he's seeing the ball and driving the ball better, and if he becomes able to yank inside fastballs into the RF bleachers.
Fun to hope.