I certainly think he's worth rolling the dice on if you are filling out the bottom couple spots on your roster. Sure he has plenty in front of him, but the fact is, sometimes it's best to draft talent and not worry about playing time. Ultimately you have to figure if he mashes AAA pitching like he did last year (albeit in a limited sample since most of his work was done in AA), and Jacobs proves to be a low batting average power guy with a bad glove he'll get a look at somepoint. It's important to note that even though Shealy is currently in his way, he is out of options, so if the Royals don't think he's worth keeping on the active roster, he'll likely be designated for assignment and claimed by another team, clearing one hurdle.
Though Ka'aihue never really showed much power before last year, it's hard to ignore his numbers last year, and the patient eye has always been there. I play in a shallow keeper league and intend on rolling the dice with my last pick just because with a patient eye like his, if he really has found his power he'll be a sneaky contributor this year. That's just my two cents, hope it helped.