I don't see much upside in Sanders. He' a QB that plays well in structure but isn't a guy that is good off schedule or getting yards with his feet. And I'm sure he has had the best coaching possible so I'm not sure he's going to get a lot better in the pros. I also wonder if a kid that grew up with that much money is going to understand the hard work it takes to be an NFL QB. That's also true of Arch Manning, so it's going to depend on a lot of things we don't know since none of us, including me, know him and what kind of person he is.
He's seems like almost the polar opposite of Ward. But, as with all QB prospects it's going to depend on character and how hard they are willing to work.