Some fair points TFG. I played again last night, but with randoms and I agree with some of what you say. The difficulty on Survivor is too easy, we played our second game on the next level up and that was much harder. It does however still lack that L4D tension and that was what I was alluding to in my OP. The hordes dont seem as full on and the specials are not a patch on L4D's - I am hoping this is just AI issues at the moment.
I agree about the cards system
I didnt have any problems with the ammo system personally. I also liked the attachment system - quite a lot of games do something similar.
I saw it was getting panned as well, but I could have predicted that no matter what. It has a high price tag and as I mentioned Turtle Rock have previous for turning off the community by implementing micro transactions\ Pay to Win. If they had priced this at £25-30 with no micro transactions I think the reception would have been more favourable.