Since I'm a huge hockey fan, I can refer to the Broncos' defense as "defence", right?
I have attended both of the Broncos' home games this season against the Chargers and the Saints. My family's seats are way up top in the north endzone, so it's easy to see all of the action unfolding. If I just had a telestrator, I could draw lines on the field and easily show the problem with the Broncos defense. It's no secret that the defense has been less than impressive this season. What's strange is that the run defense, last year's bugaboo, has actually done pretty well. The question mark lies with the pass defense.
The Broncos are on their third defensive coordinator in the last three years. Larry Coyer held the position for four years, then Jim Bates came in last year, and now Bob Slowik is the man in charge of the Orange Crush. All three guys have had their problems. This year, Slowik's defense sits dead last in the NFL in pass defense through the first three weeks. Philip Rivers and Drew Brees absolutely torched the Broncos secondary, even with All-Pro cornerbacks Champ Bailey and 'Dre Bly running up and down the field for the Broncos.
There are two glaring flaws. The first one is the pass rush. Denver's pass rush is simply non-existent. The line does a decent job of pursuing the run, but none of the four starters - John Engelberger, Marcus Thomas, DeWayne Robertson, or Elvis Dumervil - can get any pressure on opposing quarterbacks. Dumervil is actually an excellent pass rusher, but he gets no help from either tackle, so he has to battle double-teams and tight end help all the time. Ebenezer Ekuban is probably the most consistent defensive lineman, and he doesn't start for a reason that I can't figure out. When you don't get a pass rush from your front four, the quarterback has an easy time picking apart any defense.
The second glaring flaw is, to me, a schematic issue. Champ Bailey adopted a system of playing off the receiver two years ago that allows him to spy the quarterback. It works for him, as he has great closing speed. That season, he led the NFL with 10 interceptions. This year, 'Dre Bly has been using the same strategy. The problem is, the Broncos seem content to simply defend against the deep ball. Rather than close on the receivers, both cornerbacks are retreating as the receivers approach them. This allows opposing offenses to convert easy short passes of 7 or 8 yards on nearly every play. I think this is why the red zone defense has been so much better than the defense between the 20's. They don't have room to back up, so they play tighter and take away the short passes. It's great to defend against the deep ball, but I'd rather see them take the chance of giving up the deep ball than give up 8 yards on every play. If you string together 10 8-yard passes, you may as well just throw one for 80 yards. If the defense decides to play tighter coverage, I think that they will be just fine. Until that happens, we will be seeing a lot of shootout type games for the Denver Broncos.