Since the very second that 343industries released details about Halo 4 people have been skeptical (and that's not a bad thing) of the new changes that have been made to their beloved franchise. I have not seen many well founded opinions from either side of the argument so I am just going to make this thread here and add my two cents as to why both styles of threads are incredibly wrong.
I'll address the Halo 4 side of the argument first. Many people have posted comments since last year about how 343industries isn't borrowing stuff from COD and sometimes even post stuff like "CoD copied from Wolfenstien" which contribute absolutely nothing to the discussion. The truth is that, and I say this as a serious Halo fan, Halo 4 has borrowed many gameplay elements which are CLEARLY inspired by their success in the COD franchise... and why is that such a bad thing.
You see, 343industries realized that a little revitalization was in order to surge the Halo franchise to new levels of success. These changes are not going to be for everybody however and if you find yourself disliking them then that's very unfortunate.
And now in response to the people who claim to dislike Halo 4 just because of some of the newer changes. I can guarantee you with utmost certainty that just because a game incorporated killcams into its multiplayer it will not play exactly the same as COD. Same with join in progress. The ideas for faster kill times and loadouts are a little bit more debatable though. Personally I think that they can play out fine and completely differently if done correctly.
Just my two cents.