Ok.
I've played some of the PC version and....it's actually pretty good.
After seeing and reading about the lack of challenge, I opted to go for the Hardened mode off the bat.
The Xenos are doing things that I haven't seen in any video and completely belay the waves of "stupid xeno" gifs and impressions. I've had them lunge at me across half a room, duck and weave, crawl all over the walls and ceilings - and they've quite honestly fucked me up a few times now.
Each encounter is tense and I feel victorious in staying alive through it. This tension also distracts you from some of the poor animation, to the degree that unless you're genuinely stopping and watching the things intently (which is a very bad idea) you are not going to notice.
Yes, the voice work is god awful.
Yes, the animations in general are quite poor.
Yes, the game has many bugs.
But it's still quite fun. (And I don't like CoD. The last enjoyable FPS I played was Singularity). Additionally, the above points could at some point be modded / patched.
Just sharing an opinion. I think the game is being unfairly dismissed by the masses (on here anyway). Try it. Up the difficulty. Enjoy it rather than trying to meticulously spot each flaw.