There is no doubt in my mind that Zach has an NFL QB in him — but there's absolutely no guarantees walking into that draft what his rookie circumstance is gonna be anything like.
As awesome as a guy like Mahomes is so early in his career, Zach can almost be sure he won't land in that good of a situation. As great a collegiate player Zach is right now --& as translatable as his skillset looks for the next level-- the circumstances he could & quite probably would walk into — they will likely render him very ordinary looking by typical rookie standards. Maybe even subpar.
Is he really close enough to the peak of his physical manhood to play that sort of roulette with his pro career? He really needs to be closer to his physical best, imo. He's a much later-bloomer than your typical true Jr. As nice of a physical specimen as he seems right now compared to other players his age — give him two more years of growth & I think you'll see what I mean. Even one more year will change his makeup quite a bit. You do remember how much more skinny he was just last season, No?