I trust the coaching and management of a lot more AFC teams. They will be fine. Some consistent franchises there that have been doing things right for a long time.
Las Vegas lines are based on popularity as well as quality. The "quantifiable" way to examine this is head-to-head records.
IIRC, the AFC started off owning the NFC this year, but the NFC came out ahead by the end of the season.
http://espn.go.com/nfl/standings/_/t...vision/group/2
http://www.fieldgulls.com/2013/12/27...of-afc-but-are
The overall record of 34-30 against the AFC is still pretty close, and it's not as cut-and-dry as saying, "The NFC is just clearly better." I believe that the NFC is stronger at the top, not quite as weak at the bottom, but probably also has a couple "posers" that are about to win their divisions as a result of squeaking by bad teams. (Chicago is probably terrible.)
The NFC West absolutely dominated the AFC South [other than that the AFC was even or better]