I don't think Kaaya is "un-athletic" or that his inability to run was the source of his failure. He just seemed to have no balance, like he suffered from vertigo or something. If an offensive lineman merely bumped into him, he would topple over. He didn't , for the most part, look shell-shocked in the pocket, he was just a weeble - wobble who would tip sideways upon contact.
He is incredibly unathletic. Balance is a big component of athleticism. So is quickness and speed. He lacked all of those things about as badly as any P5 QB could.
He got by on his technique and arm and smarts. He was a pretty accurate thrower with a good arm who usually knew where to go with the ball. But his athleticism is off the charts bad.
Good point on balance being a part of athletic. What I mean is that I don't think Kaaya was without athletic potential. He passed the eyeball test, and I thought he was the type of qb who COULD run if he wanted to, but it was not part of his qb repertoire. Some site says he ran a 4.8 40 out of high school, which I think is actually faster than Perry's time. Then I actually saw him run in a game and thought, "Does he have bunions or something? Is this a joke?" Don't understand how he could be so slow footed. He looked like an athlete, but obviously the results showed otherwise. Even with the slow footedness, I think his biggest flaw was that he would fall over in a stiff breeze. You don't have to run to be successful, but you sure as **** can't lose your balance whenever a player touches your uniform.