I kinda liked the underwater stuff, I thought it looked interesting. Visually it was merely ok-to-good, but I'm a sucker for those elaborate set pieces. I do completely agree that CoD is way, way too dependent on riffing on established sequences: this was totally All Ghillied Up Part III Electric Bugaloo. If ppl are calling this stuff tired I have no problem seeing that point of view, maybe it helps I skipped the last CoD entirely.
The dog stuff looked worse visually and I dunno, something about having that dog kill dudes for you felt weird, which is obviously a strange reaction. If I'm playing a game and am about to die before a dog saves me it's great, but something about this setting makes using the dog to kill a seemingly unarmed guy walking down a path on the woods kind almost... icky.
I agree the story will almost certainly suck ass, MW2 especially was a totally fucking gibberish plot poorly told, but maybe the story being far enough removed from actual reality will help. This is basically post apocalyptic near future scifi now.