Well it depends. It depends on what you like. If you like multiplayer games and such that allow you to play with others online all over the world, then no. From what I've seen the only differences besides graphics and points is the system that you use to unlock stuff. Unlike Reach, you don't have to buy your new armor and such. You simply unlock it after reaching a rank. Which I think is cool and far funner.
Now as far as storyline is concerned, it isn't just another cash cow that they're trying to milk. Idk if you played any of the previous Halo games, but in Halo 3, The Master Chief and Cortana went MIA. Then, four years later, in this game, Halo 4, The Master Chief and Cortana return.
The storyline thus far has told the player that after Halo 3, when The Master Chief used the UNSC frigate, Forward Unto Dawn to save the galaxy from Forerunner race, only half the ship made it through slipspace to earth. Unfortunately it wasn't The Master Chiefs half and he and Cortana were left behind. At this time, The Master Chief was put into cryogenic sleep and stayed that way for four years until Cortana awoke him due to a covenant attack on the ship.
That's where Halo 4 begins. There is a lot more to the story, but in order to find out, you're just gonna have to play the game and see what happens.