I am not going to re-visit the nonsensical comparison of Goff vs Stafford because both are good QBs. Stafford is an elite QB who has his warts. Goff is a high tier two QB who is better than most care to perceive him as being.
Both are system QBs, and both are successful when played within the confines of their respective systems. All I will say is that Goff is blossoming in Detroit. He has a HC who trusts him. I've watched a number of Detroit games. It is common to see Goff change the play at the LOS, something he was not able to do under McVay as a consequence his INTs are way down ever since he's been in Detroit. IMO Mayfield and Goff are comparable in terms of their respective talents. Mayfield is earning McVay's trust because he's a scheme fit in ways Goff wasn't.
Baker is a high tier two QB as is Jared. Both are progression read type of QBs. If you want to compare apples to apples then compare Goff and Baker. Goff showed in 2018 he's capable of leading a team to the Super Bowl. So the question of whether can Mayfield do likewise is the question we should be asking. IMO the answer is yes Baker is as much of a Super Bowl caliber talent as Jared and the way the Ram roster is loaded with talent there is no reason to think Mayfield isn't good enough to be a Super Bowl winner.
The wildcard with the Rams is the defense. For how much talent there is on the defense, they are being sabotaged by poor coaching. With AD, Wagner, and Ramsey, 3 HOF caliber players, one on each level this defense should be a top 5 unit but it's nowhere near that. Raheem has shown he can play an aggressive style when he wants to, but he refuses to do so in most games.
If the Rams are serious about another SB run they need a new DC. One who will take the time to know his players in terms of talent. The emergence of Hoecht and Durant is an indictment of Morris. He continued to play Lewis and Kendrick despite having better players in Hoecht, Durant, and Rochell. Why did it take so long for him to see it? Because of his good enough attitude that's why.
Goff was doomed the day McVay was hired. He wasn't McVay's choice for a QB. Baker Mayfield is clearly McVay's choice as was Matt Stafford. In all likelihood, Stafford has one more season as the Rams QB. Baker will be his understudy and the eventual starter this coming season. From McVay's comments, Mayfield is the QB he wants as he has the arm talent, and the intelligence to grasp McVay's offense and play within it in ways even Stafford doesn't.
I think McVay's offense under Baker will be primarily a mid-range pass attack with occasional deep strikes. Baker has the accuracy to hit a receiver in stride and turn a 15-20 yard pass into a 40 yd play. If the deep strike is there then Baker will be expected to take the shot as he did with Jefferson in the last play of the Raider game. That showed me something that wasn't part of Baker's game in Cleveland. He could read that his number 1 read was going to break open. That is exactly how McVay wants his offense to function. If the deep shot is there from his early read then take the shot, if not focus upon the mid-range routes.
Akers is making his case to be the #1 RB and with Williams they have a very good #2. IMO they will draft or sign a FA #3 RB. Mayfield played well enough to win 2 regular season games with backup WRs and OL. IMO that will be good enough for McVay. Both Goff and Stafford IMO would have struggled to do likewise under those circumstances.
That's why I for one feel confident in a Mayfield led offense going forward. If he can play this good with a backup OL and WRs then imagine how good he can be with a good OL, Kupp and Robinson back. I think Mayfield will spread the ball around moreso than Stafford who has Kupp tunnel vision. We could see the return of the 2018 type of offense under Mayfield.