Another thing that can be added to Spectre's list is the leaderboards; why do IW's games collate the rankings by score only? All this does is reflect who plays the game more than others. At least with Treyarch, the rankings hold more merit with SPM over duration of all-time, monthly and weekly. It's to me a more accurate depiction of quality rather than who has more time on their hands to play.
I was in the top 75 Domination rankings on Black Ops with a SPM of around 850 which was a very satisfying but for me to replicate that feat on Ghosts; I'd have to be playing at least 12 hours a day every single day just to match the players in the score-based leaderboard. It's not a crushing problem but it's another feature that isn't as well implemented as what Treyarch have done.
Basically anything in Barracks sucks the big one!