Goff looked like ass last year because he literally had zero weapons to throw to and the o-line couldn't run block at all for Gurley. Thats why they went out and drafted Cooper Kupp and then got Sammie Watkins from Buffalo. Now, he's leading LA into the playoffs and could be the NFC favorite to make the Super Bowl.
Your statement on Jackson's ability to play AFC North ball is valid. But I don't agree that he relies on his legs too much. In 2017, his QB rating was 151 (Rosen, 147 rating) and threw for 300 less passing yards than Rosen despite throwing 50 less passes. Yeah, Jackson can run the hell out of the ball but numbers show that he doesn't overly rely on his legs to get the job done.
The QB people need to not forget about is Josh Allen. He had a down year in 2017 and that could make him fall in the draft. If he is there in the late first, I wouldn't be surprised if Pittsburgh drafted him for the post Big Ben era.