Comparing Goff and Stafford isn't fair because the innate talent levels are simply different.
Stafford is a much more talented QB than Goff. Goff isn't a bad or untalented NFL QB. He's just not to the level of Matthew Stafford and won't be because he doesn't possess Stafford's canon arm or quick release, the ability to throw at multiple arm angles, or Stafford's ability to process the game so rapidly. We've probably seen about all Goff has.... and it's not his fault. It's like comparing Aaron Donald to most any other NFL DT. It's unfair. Donald has incredible strength, the quickness of a RB, the speed of a LB, and the footwork of a DB. You're either born with it or you're not.