Well, the offense is getting changed. Dennison runs a Kubiak offense. Which is great but no one knows how that would work with Tyrod. So don't assume everything will be the same.
Also, Bills will have let Robert Woods (likely), Goodwin, Hogan, and Harvin all walk out the door. Who is going to catch the football? Do you assume Sammy is healthy?
If you use your first pick on a WR then you have huge holes in your defense. When you pay Tyrod it leaves no money for free agency.