The bad news is I don't think Denver is really going to fall off much.
In 2016 the Broncos:
Have less than 11 million dollars in cap room.
Have the following key players hitting FA:
Von Miller
Evan Mathis
Brock Osweiler
Ronnie Hillman
Brandon Marshall
Malik Jackson
Danny Trevathan
C.J. Anderson
Brandon McManus
Oh! That's great! They will be forced to lose some of these players, right?
Probably not, because Manning retires and their cap space jumps up to $30 million.
I'm going to guess they lose maybe Jackson or Trevathan, as both will be wanting large-ish money in FA. Von will get paid and they can afford the rest, provided no one offers a huge deal for Brock.
They can also dump the aging DeMarcus Ware and their cap goes up to $40 mil.