Best chance for Goffs' success is a hopeful level of. Extreme preparation and coordination with his receivers to a degree where any action by defence is has a innate reflex answer including a throw away if necessary.
I believe he can become a QB capable of carrying a team although I also believe his choice at #1 was somewhat inflated.
The McVay offence will provide enough options to help him succeed.
He will need more success in the running game and fewer drops by receivers.
That means all of our receivers need to work to become polished, reliable , and clutch. Able to be the guy on any given play as far as a must 1st down or touchdown.
I don't think Goff will be holding the ball quite as long this year.
Hence the OL won't be quite as challenged in the pass blocking.
I hope success is less about the protection and more about the QB and the receivers being at the top of their game.
That's the easiest way to improvement I can see.
I think Goff can get there this year that way and we'll refine the OL over the next few years to make things more top notch.