I don't know, Ghosts is a new idea with a new campaign so hopefully Infinity Ward talked about the problems in the Modern Warfare series and are doing what they can to cancel out. Also, hopefully with a new game comes new ideas, so that's something I will be looking forward to.
Battlefield 4 I will definitely buy, the series seems to be headed in the right direction and Battlefield doesn't really experience the problems that CoD does. If you are a first time Battlefield player and BF4 will be your first game, I recommend you pick up BF3 or BF2 to get used to the game and the controls before you spend money on BF4, because it does take a while to get in to. I know that in the majority of games, you need to get in to them, but this goes for Battlefield especially.