I dislike most of the changes. The campaign feels like it is on repeat from all other Halo games. And what's up with the covenants, they have like no new tricks since the war ended... oops sorry, the Brutes are gone. Also the Prometheans, I really don't remember them until I face them in battle, empty without a soul. Spartan Ops has no intense feeling like Firefight had, and I don't need the whole game to be tied up by story.
Multiplayer is by far the worst. Overpowered weapons, getting thrown in already started matches, no ranking system, no social slayer, level up to unlock better skills for your spartan, sneaking is not an option since promethean vision reveals your location and your shields goes down faster than you can run.
I can understand that 343 wants to go their own way as far from Bungie as ever, but when you have a rock solid ground to build on. Don't let it slip away that easy. If the game needs an update 2 months after the release, then it is very clear what has happend. The game is not complete. But then again, I don't think Microsoft could wait that long to sell thousands of Xbox 360 consoles along with Halo 4.
I really like Halo: Reach so much more than Halo 4, it pains me to say how high hopes I had for Halo 4 and they all fell apart after my first day with Halo 4. The best part about Halo 4 is the Forward Unto Dawn (live action series). I think it's just great and well made.