BO2 has great score streaks, and the leveling system as well as in game achievements are hands down better than Ghost. Ghost has far better hit detection and less problems with lag compensation hands down.
This weekend I went back and played some MW3 on PS3... Terrible lag, Worse spawns than Ghosts, Maps with even more blind spots, hackers (invisible players!)
I think people looking back at old games are feeling nostalgia. Ghost isn't perfect, but I see the progression.