What the "Fernando sucks" crowd seems to forget is that Nando's troubles at Cal were due to having an incompetent head coach and a porous OLine (no offense to the guys on that line). At IU, where he had good coaching and an OLine that could actually stop a pass rush, Nando was able to show off his arm talent. Now, I'm not saying Nando will be an all-time great or even a franchise QB. That's always hard to predict. But if Nando works as hard as he did in college and gets some breaks, he's likely to become a better than average or even better than "good" QB.
Of course, Nando will need a good coaching staff as well as a solid OLine. I haven't followed the Raiders in years. I'm not sure what their OLine situation is, now. But if they selected a QB with the first pick of the draft, I'd suspect the OLine isn't that great. For that reason, I suspect whoever is playing under center for the Raiders will struggle this year. Also, from what I've read, it looks like the Raiders installed a new head coach (and coaching staff?); the jury's still out on how they will perform. Basically, this year reads as a development year for the Vegas squad.
For Fernando's sake, I hope that he gets to sit behind Kirk Cousins for a couple years so that he can learn the NFL game and develop in practice before he becomes the Raiders's starting QB. Basically, his path to success is likely to follow the Aaron Rodgers route and learn from the sidelines, first.
That said, given he was the #1 overall draft pick, the Raiders will likely throw him to the wolves sometime this year. They may start Cousins for six or eight games then they'll give the reins to Nando once the Raiders have proven to be an utter disaster, yet again. Nando will take a beating and may become gun shy. For that reason alone, I suspect Nando will not reach his ceiling and could end up proving his doubters (especially those on this board) right.