I rarely chime in on these forums but after watching the Halo 4 footage (and getting hyped) I feel like I HAVE to make this point, 343 if you are out there PLEASE PLEASE consider this post...
The argument I make for Halo > COD (in particular Halo 3 > COD4 when they were semi competing) is that Halo shines because it is purely a SKILL BASED GAME. Learning how to BR properly was critical in being a good player and instead of rewarding players for getting the first shot ,like in COD, you had to be poised, cunning and have good aim to win a BR battle.
I was an avid Halo 3 player and had level 50 in multiple playlists and the reason I think Halo 2 and 3 were so addicting for me was because of the leveling system. It creates a sense of competition and 80% of the time being of a higher level than someone meant you were better at playing the game (a game where BRing is the core skill). The Halo 2/3 level system pushed me to get better at the game, made me aware that I wasn't good because I wasn't level 50 yet. I had to hone my BRing and learn how to play with my team/partners in order to up my level.
This is why Halo Reach didn't really engross me, because it lacked a leveling system. This was so for 2 reasons:
1. If I just wanted to pick up and play without my team in a normal non-arena playlist, it would be almost trivially easy to carry my team even in 5 v 5 because there was no matching based on skill.
2. There was no sense of progression or mastery of Reach, yeah I had my stats and yeah there was the COD style "keep on trucking" rank system but what keeps me addicted and loyal to a shooter is the urge to prove that I am better than the kids I'm playing against and to some degree better than the kids on my friends list.
343 I PROMISE YOU the longevity of Halo 4 will be benefit from a leveling system akin to that of Halo 2 and Halo 3. Yes I know the drawback of people selling accounts or people boosting levels but at the end of the day the people doing that are those who are so addicted to leveling that they do it to earn money. In fact if you think about it there was a demand for a level 50 account because it's something that ALL players wanted. Do not do any arena shit, don't do any spartan vs elite shit just have playlists with levels and then if anything your rank can be universal to help noobs feel good about themselves.
I love Halo, I really do but a big part of why I love it is because of the competitive spirit and with Halo 4 looking very good I would hate for a game of such quality to not live up to it's potential because a simple level system was missing.
PS: If Halo 4 does have Halo 2/3 style leveling, I am sorry for ranting.