I know this post is your opinion but you make it seem like it’s a guarantee for all rookies. If Fields started the season, he very well could have a Herbert or Prescott type of rookie season. Because of his athleticism and accuracy, he might allow for all weapons on the offense to increase their stats.
I don’t think using Hurts, Jackson, Young or Newton are good examples. They came from college programs where they were used as runners. Running has always been in their DNA. Fields has always been pass first. He does use his legs, but isn’t always looking to run and I think that will transition into the NFL.
I also don’t think you would have to throw a lot at him his rookie year. If the running game stays consistent, I think a mixture of simple concepts can go a long way. A couple of athletic plays, accurate balls and connections on deep passes can make defenses back off. A big reason the offense was terrible under Glennon, Trubisky, Foles was because of accuracy issues and no deep balls.