Dak is a mobile QB in EXACTLY the way the term is used today. Threat with the legs but doesn't depend on running. He's not RGIII or Tyrod, who would be running quarterbacks. You said it yourself, he's amazing when rolling out. Dak's legs are an absolute threat and whether he runs 1 time a game or 10, defenses have to account for it. That's what makes the RPO and play-action rollouts work, and that's what makes him different than Brady. Feeding on short and intermediate routes and using his legs as a threat makes him more like Jeff Garcia than it does Tom Brady. He's better than Garcia, obviously, but his playing style is absolutely nothing like Brady.
To be honest I don't care what Brady did in 2001 and 2002. That was two generations of football ago, and saying he's a Brady in the making is just a massive reach at this point in his career. The reality is that Dak has never been successful when he didn't have a run game to lean on and until he does that, he has no business being compared to the elite quarterbacks of the last decade.
I'd compare him to McNabb, but not McNair. I'd also compare him to Aaron Rodgers, Alex Smith, Brett Favre and Tony Romo long before I would Brady, Brees, and Peyton or, on the flip side, Mike Vick. But he's most similar in stature and play style to Newton. So kill that lazy comp nonsense.