I've played most of them, but the only ones I liked were 3 and Wars.
I hate the 4th one. It is the essence of CoD. 3 is my favourite and I loved wars too. I thought ODST was highly underrated as well. I can't comment on 2 because I could never be bothered to finish it, I'd just lose interest.
Did they add iron sights?
Nah. They added killstreak weapons, perks, customised loadouts, removed fixed placement of weapons to make the game have no strategy. All the maps are god awful so that every game is just continuously getting funneled into a killzone and seeing how many you can take down with you. Basically all the strategy is gone, and it's poorly optimised, I can't even play split screen without a noticeable guaranteed lag. Shields deplete insanely fast so there is next to no chance of escaping enemy fire, and I just hate how awful the pacing is in general. --- http://www.youtube.com/watch?v=-_ONVOTwt0k#t=03m49s
LR: looks slow, graphics look kind of washed out and faded, combat system looks clunky.
Versus: Improved character models, ATB system, and pet system.
^ This is a fanmade game for FFXIIIversus.
My verdict is... that is a joke. That's no how SE makes that way. Only SE can work on their term is technology. This vid is a fanmade game, a game design for fun and other purpose.
^ This is official trailer of LR:FFXIII. Toriyama and SE team/group has been worked so harder for the final chapter of this game. It's not cheaper or anything at all. It's very expensive in making FFXIII series and everything.
My verdict is... I'm looking forward to it because it is a real deal and a real game. --- "Get up!! Show me your true power!" Ryu's victory in SF3