Let me rephrase the question from a Broncos perspective: "Did we play nickel 65% of the time in 2012 because we don't have a true Monster in the Middle, or did we play nickel 65% of the time because the opposing offenses dictated nickel & dime coverage with 10 & 11 offensive sets?"
Conventional wisdom seems to suggest that when an offense goes to a 10 or 11 personnel package, the defense counters with the nickel. With so many teams running these offenses lately, is the Mike on the endangered list?
Here, a reporter asks JDR this point blank (are true Monsters in the Middle endangered?); check out JDR's response at the 6:20 mark in his video on DenverBroncos.com: (I tried to type this out as fast as I could go, it's pretty much word for word but not perfect):
I don't think (the Mike) is endangered. If you have a special mike who is a special player they will play every down. Patrick Willis doesn't come off the field for San Francisco. So there are guys out there that are superior players; but if you don't have a guy who is a bona fide monster in the middle that is never going to come off the field, then he can be the first guy off. So you are going to play your 2 strongest guys all the time if they can handle it, and the 3rd guy whoever that is needs to play when it's base and come off when not. It doesn't have to be the mike though, it can be the Will or the Sam that comes off, it varies by team.
(Note: Patrick plays in a 3-4, so it's not the best answer to the question...)
Looking at clips of games last year...it's apparent that Woodyard is effectively our best LB (who never comes off the field). He plays in base formations as WLB, and when we go 42 or 52, he is the "mike" LB responsible for intermediate zone coverage (the other LB has man coverage on the TE in 42 or 52); and when we go to 4-1-6 he is the only LB. Woodyard is our best LB & JDR uses him as such (I'm obviously not comparing Miller & Woodyard; they aren't used comparably; Von was used as a DE 85% of the time, only 15% of the time dropping back in coverage, as Topher Doll points out).
So, when you are on ESPN and some simpleton blasts the Broncos for not drafting a MLB, your first rightful response is: "It Doesn't matter, we played nickel & dime 70+% of the time last year."
But the more interesting question is...would we have played more of the time with only 4 DB's if we had better LB's? I'm not sure it's an easy answer...
Check out the game film below, borrowed from BroncoMike's article on the Front 7. Look at these 10 &11 personnel groupings, and yet with only 4 db's on the field, clearly showing JDR isn't afraid to use a 7 man front & 4 db's against 10 & 11 personnel groupings.
Note: you could argue these pictures are from when the base 4-3 was just caught on the field against a hurry-up, but for speculation's sake, let's not.
Here's a 4-3-4 against the Saints "11."
If I violated any posting rules, be easy on me, never done this before.