Mahomes has incredible talent but is starting to go unchecked with his running outside the pocket even without pressure. That's why he's starting to throw interceptions, as every quarterback, including Aaron Rodgers, is more efficient and less mistake-prone if they can hit someone in a designed decision rather than an improvised backyard style of football. Even if he can still throw accurately on the run, chaos is generally not a good thing and more prone to luck (we saw both sides of that, with one ending in an interception and one ending in a deep touchdown pass to Hunt.) Montana, Brady, Manning, and Brees all learned to beat defenses in the pocket based on out-thinking them, and even great scrambling quarterbacks (like Rodgers) realize they can't rely on improvisational, pocket escaping football but can use it in their back of tricks when necessary.
I think Mahomes is one of the most talented quarterbacks to come into the league, though others have pointed out players like RGIII and Kaepernick; even in the last few years look at the difference with Derek Carr and Dak Prescott with and without great protection and playmakers. I think Mahomes will be a starter in the league for a long time, barring injuries, but if he doesn't learn to be disciplined in making throws within three seconds, he'll end up just another guy who looked unstoppable but got figured out.
