i suppose it depends on how you define "good nba player." if "good nba player" means a guy who effectively fills his role, then yeah, i could see jimmer becoming a "good nba player," though it's unlikely to happen as soon as this coming season. if he isn't traded in the offseason, i expect jimmer will get lost in the shuffle while new ownership sorts out this mess of a roster. his handle's nowhere near adequate enough to play pg. his size is nowhere near adequate enough to play sg. so he clearly shouldn't be starting at this stage of his career, which leaves him in a reserve role on a team still chock full of combo guards who like to chuck...
even if the kings theoretically trade marcus thornton and let toney douglas walk, there's still the potential for the kings to draft a guard in this draft. there's still the potential for tyreke to be shifted back to pg. they could sign someone. they could trade for someone. they could bring back douglas. who knows? it leaves jimmer in an extremely vulnerable position, as his minutes will always be jeopardized by players with more nba-ready athleticism, size, and skillsets...