I personally thought infinity ward massively improved since CoD 5. I thought it was a great game. Yes, the gameplay is the same, but what really hass to be different about it? It's the same engine and same gameplay with new features and a better multiplayer, IMO. The story was unique and I thought the characters were done well.
Also, don't hate a game just because the playerbase is 12 years old and annoying (which it mostly isn't). Runescape has annoying people that play it, yes. WoW has devoted assholes, yes. Call of Duty has racist screaming 9 year olds, yes, but that doesn't make them bad games.
I don't think they are milking the franchise for money either. They wouldn't have put that much effort into making a longer campaign, better multiplayer, easter eggs and a different type of storyline than they have been if they were only doing it for the money.