Wentz was a 2 year starter and in the program 5 years. So, his familiarity with pro style concepts is light years ahead of Goff. It's not even close.
The reason Wentz has 23 starts is because he broke his wrist on a freak play going out of bounds. He still fought his way back and played in the Championship game and led his team to the National Championship. With that broken wrist, even in going 10-22, iirc, he threw some ridiculous throws including one sideline throw that is easily a top 10 NFL QB throw. With a broken wrist.
Yes, the good news with Goff is that he was in a program that preferred yoga to weight training because he has a digestive defect in how he processes proteins which made it nearly impossible to put on additional muscle mass. A weight training program with such a defect would have put him in nutritional distress and likely would have led to injury. So, in that respect, Cal was the perfect place for him even if his OL made it uncomfortable. However, just saying "he can put on weight" isn't accurate. For a QB who's never really been in a weight program before, integrating a weight program isn't a slam dunk. It's a transition and no transition is guaranteed. Will it be difficult? I doubt it. That said, it's important to understand that there are time elements that can't be sloughed off. His body type is asking to be battered in the NFL, especially because he's not bulked up. Warner tried going the leaner Pilates route and after the season, he said it was the worst he'd ever felt. That bulk makes a difference. Asking a LB to add 10-15 lbs isn't any big deal. He's likely been hangin' and bangin' in weight rooms since HS or earlier. Asking a QB who's never been a lifter to go into an NFL weight room and put on that weight in muscle is a MUCH bigger deal because that weight can't affect his throwing or ball (flight) mechanics, footwork, speed, or flexibility, . To add that much muscle without losing anything takes TIME and a PLAN. I fully believe Goff can and will do it. But it won't be before September. If anything, it's Goff who's going to need a year to sit and learn. That's just what's real. He may have been playing behind a crap OL, but he wasn't playing Seattle, SF or AZ 6 times a year. The 20 lb difference between Wentz and Goff at the NFL level is massive.
When it comes to experience, I acknowledge that Goff has played 3 years to Wentz's 2. That said, there are other factors. Wentz has 5 years depth in a pro system to Goff's zero. As well, QBs play in a system. Goff played in a Bear Raid spread system that was going to generate a lot of pass attempts. Many of those pass attempts bear no relation to the NFL game and when it comes to evaluating talent, don't yield any meaningful information. If they did, guys like Timmy Chang and others from similar systems who've put up similar or better numbers would be populating the NFL in greater numbers. Rather, it is the other things Goff does and does well that put him near the top and require consideration. So rather than "experience" per se (we've got 2 of the top 10 all time NCAA yardage leaders on the team already including the all-time NCAA leader in Case Keenum), better to focus on what makes each of them special. And rest assured, they both are special.
I would agree with the several evaluators who graded them both ahead of Winston and Mariotta. I agree. I like them both better. I know many don't. Well, I think Winston was more ready than Goff right away, but over all, yeah.