1. Denver was a decent team BP (Before Peyton). We all know how good he is, but what has happened to the rest of the offense to raise it's level of play so well?
One shouldn't forget the addition of two free agent tight ends as well, Joel Dreessen and Jacob Tamme, who came in and immediately made an impact, Tamme as a receiving TE and Dreessen as a guy who can do it all, especially in the Red Zone.
So far this season when Peyton has struggled it's been for two reasons. The first is when opposing secondaries get aggressive and physical with the receivers since most of Manning's routes are timing routes, so throw the timing and route off and you'll get interceptions. Of Manning's 10 interceptions, 6 have come when the route has been disrupted by physical coverage.
The second thing opposing teams have done is attack the right side of the line. The current starting RG Chris Kuper is out with injury and his replacement Manny Rameriz is only a decent pass protector. At right tackle you have a great run blocker in Orlando Franklin but he's only average in terms of pass protection. Attacking that side often has lead the most of the pressures on Manning (9 of his 19 sacks have come from just those two players).
At this point in the season I'd say the Broncos safeties. While Mike Adams and Rahim Moore are playing well, both tend to struggle in deep zone coverage and get beat. They aren't slouches by any means, but against a QB who can look of a safety is going to be able to pick these guys apart. Add in that Adams spends about half his snaps in the box or blitzing usually means Moore is a single high safety. If Flacco can build off the play action and look off Moore, I wouldn't be surprised if Torrey Smith can get open deep 2-3 times this game. Few teams get beat deep more often than the Broncos, but that does mean that Von Miller and the pass will have more time to get to Flacco.
On offense I'd go with Joel Dreessen. At tight end he's currently tied for 2nd on the team in receiving touchdowns with five and is one of Peyton's favorite targets in the Red Zone since he's a great blocker and receiver. He won't get a lot of targets, but on 3rd down and in the red zone, he's deadly.
On defense I'm going with D.J. Williams. Now Williams is the former starting WLB but missed half the season due to suspension. Now that he's returned he's spending his snaps at both WLB and MLB, with most of his time in coverage. He'll likely be the one tasked to cover Dennis Pitta or Ray Rice, and because these guys are playmakers Williams is going to need a great game to contain them.
Broncos 27-17. I think that had the Broncos faced the Ravens early in the season it would be much closer, if not going to the Ravens, but with a beat up secondary and going into the 1st week under a new offensive coordinator, I think the Broncos have the edge. I think the Broncos defense will be able to get after Joe Flacco, and while I doubt the Broncos will be able to stop the Ravens offense, I do think they can slow them down enough to get ahead and hold that lead.
It should be an exciting game, and if the Ravens can run the ball and go deep often, they might be able to keep up with Manning and the Broncos offense.