I think the entire Broncos passing game should be downgraded significantly. This has more to do with not having Cutler back slinging the ball downfield than anything bad about Orton or Simms. Orton/Simms will be decent enough replacements to keep the WR's from dropping completely off the radar, but the numbers overall will definitely be lower than last year. Orton/Simms should be a solid #2 QB and may even creep in as a bottom tier #1 in large leagues. Denver's running game could get a boost, but if McDaniels uses the RBBC that was used in New England, the individual backs will be little more than #3 fantasy RB's. I wouldn't worry about Scheffler. Rumors out of Denver are that McDaniels doesn't think he fits his system and has been looking to trade him as well.
Cutler needs to be downgraded from last season, however, he should still produce good numbers. I agree with above that Olsen should be a big benefactor. Earl Bennett could end up being the best WR because he and Cutler already know each other. The boom or bust guy will be Hester. By boom or bust, I mean he WILL have great games, and he will disappear in some games. He's got the speed, and now has a QB that can hit him in stride. As Hester gets better as a WR, he will improve and could become a superstar, so if you are in a dynasty league, I would go high on Hester. If you are in a re-draft, he should go in the 2nd or 3rd tier of WR's. Forte should put up really good numbers as well. Cutler's arm will make other defense fear the pass and Cutler will hit Hester long just enough times to make the lanes open up for Forte.