I get Battlefield 1942.  It was the beginning, set in World War II.

I get Battlefield Vietnam.  Even the Vietnam setting, including a fast-forward of a few decades forward in time.

I get Battlefield 2.  Modern-day settings.

I get Battlefield 2142.  Future setting.

I did not fully get Battlefield 3.  Modern-day setting again, but at least a nice graphics and physics engine.

I don't get Battlefield 4 at all.  The graphical updates are subtle enough that many people cannot tell the difference between it and its predecessor.  I see threads on forums of people getting excited about this game and what are they discussing?  ...what guns will be carried over from Battlefield 3 to Battlefield 4.  Or, in other words, what parts of the new game will be almost exactly like the "old" game.

I don't get it.