I feel like it was the start of the backlash of more serious gamers, against the perceived 'churn 'em out' nature of CoD titles. MW and Blops had been huge, and CoD overall was huge for both the casual and hardcore MP gamers, but Ghosts was more about the new campaign storyline, and a new horde mode (not zombies or spec ops), and made some minor changes to player character movement (e.g
'Call of Duty: Ghosts' mostly plays it safe, but an improved multiplayer experience makes up for the disappointing campaign.
-No history on 'Ghosts'. They're just some elite unit of spec ops guys (I guess) with no real exploits other than one battle. No epic tales of many battles won. Just a 2 minute animated sequence at the beginning of the campaign. -spoiler-spoiler-I had zero interest in any of the characters. Compare/contrast to how you felt about Price and Soap.