The biggest danger with Kyler Murray is he takes a concussion, freaks out, and retires from football like Chris Borland did. Unlike Borland, Murray has a lucrative alternative option to football. If he takes one or a series of concussions, CTE is such a bogeyman nowadays (for good reason), you never know.
I'm not worried about him getting benched and then quitting as a result, or him quitting because he sucks. If that happens he'll be doing you a favor so that you're not somehow finding yourself devoting 7 years to a mediocre-at-best player.
I don't necessarily think Murray is at higher risk of concussion than most other QBs. I think his speed, awareness, willingness to make business decisions, and his musculature are all factors that reduce this risk. But it can happen to anyone and the odds are it will happen to every QB at some point in their career.
On the football field the biggest risk with Kyler Murray is he ends up holding onto the football for too long, unable to read the field in a timely manner. It's the one trait that could be one way in college and then flip the total other direction in the pros. You don't suddenly become inaccurate, or suddenly become bad at making people miss. You don't suddenly become a weak-armed thrower. But you can go from a guy who could get the ball out quickly in college to a guy who can't get it out quickly in the pros.
And if Kyler Murray falls into that trap, at worst he's Tyrod Taylor with a better deep ball.
His best though, is practically unfathomable.
If he gets the ball out and displays the sort of quick process he's shown in college, or heaven forbid even gets better in that regard (as he was only a first year starter), then his ceiling will be dictated by his physical skill set, including stuff like accuracy and touch, and that is staggering. Lincoln Riley is *NOT* wrong to say that he's never seen this package of elusiveness, speed, intelligence, and throwing skill before; that it's unique.
There are negatives with the height. I've probably detailed more poor throws that were sourced in Kyler Murray's deficiencies than most of his detractors. The biggest concern lies at the intersection of his short stature and his tendency to miss high, or to have high ball placement. But it's not a major concern because the bottom line is, he's an accurate thrower of the football. Everyone misses sometimes, and I don't know that it particularly matters why. What matters more is how often.