Great posts Azaxx. Great point about Halo 2. I love that game, but the online had a lot of issues. Super jumps, people using the standby trick, etc. The noob combo was so overpowered. Like I said, great game, but it definitely had it's share of problems.
I think Halo 4 is great. Yes there are some things wrong with it, but overall a stellar first effort by 343i.
Now in terms of things I don't like that I would change....
-Bring back campaign scoring, I liked it in the last 3 Halo games (3, ODST, Reach).
-I would love theater mode in Spartan Ops and Campaign. I really want to make a clip of me assassinating a watcher.
-The first ten weeks of Spartan Ops should be playable by everyone. It's on the disc and like Firefight should be playable in split screen or over LAN. My 10 year old nephew doesn't have a Gold account (his parents choice and I agree with them), but he is allowed to play Halo. I know he would like to play Spartan Ops.
There are some more obvious problems - online stuff (lag, etc.), but that isn't all the devs fault. In terms of the "cheapness" of some weapons (boltshot), I just need to be smarter when playing online. I was a little unhappy with some of the COD style additions to Multi, but this game still plays like Halo. I also noticed all the "perks" are quickly unlocked and the specializations aren't overpowered. I liked the story, but I also watched all the terminal videos, I am reading the second book of the Forerunner trilogy and I devour most things Halo. I am not sure if that added to my enjoyment of Halo 4, but it might have helped.
Once again, spectacular first effort by 343i and I look forward to Halo 5.
On a side note, as I have been playing through Spartan Ops I have become aware that the A.I. of Infinity (Roland) is unlike the other A.I.'s in Halo. Even Cortana as "human" as she is doesn't act like a 12 year old. During the Ops missions Roland's comments are annoying to say the least. Other A.I.'s (Cortana, Auntie DOT, and Serina from Halo Wars) are condescending at times, but not childish. Also Spartan Miller is a wuss. I like Palmer, Capt. Lasky, Halsey and the other Spartans.