-Bloom
-Cartoon Graffics (FTL!)
-Maps I could easily puke over (side note: way to go bungie for making EVERY OTHER FREAKING MAP in dull, bland, forge world. Damn it Bungie)
-Melee system-without your shots bleeding through when you melee it just makes it a big melee-fest in mid to close quarters and it gets hella annoying. (and I'd even go so far as to say the actual mechanic/animation of you meleeing is bad, its almost like you throw your spartan off balance)
-Mini-nuke grenades, the only reason some people like reach, they can get 15 kills without shooting.
-and like 50 other things....