I personally think Advanced Warfare is the worst, considering how unbalanced and annoying the multiplayer is. I also think the movement system is very unpolished and bumpy.
I think Infinite Warfare is the second worst because it's just a copy of Bo3, but in my opinion just more boring. Sure the supply drop system is better, but something about the game that I can't name just makes me feel uninterested whenever I play it.
I've never played ghosts but I heard it's pretty awful, so I put it on the pull. At least it's boots on the ground though. I would probably put it as the third worst, just from what I've heard.
Bo3 imo had the opportunity to be great, but the supply drop system held it back quite a bit. Other than the supply drops and the somewhat unbalanced multiplayer, I thought it was an okay game, so I would put it at the number four spot. I'm just happy MWR is out this year.
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Well I'm more of a single player person so in terms of the campaigns, I felt CoD 3 had the worst out of all I've played. Yeah I know it's not part of your poll but it was incredibly short compared to CoD 2 plus those annoying quick time events? Completely unneccesary. Likewise the second numbered CoD had the best of all I've played simply due to the depth of each mission and the sheer amount of them.