If your not up for a lengthy read, there is a TL:DR (too long:didnt read) At the end of my post.
To begin with, Halo 4’s gameplay feel/mechanics. I would like a fast-paced gameplay, with high player speeds like Halo 3, high jump heigths, like Halo 3, high weapon damage, like Halo 3(if not higher) and i would like to see more small-scaled maps, aswell as more sniper rifles on maps.
Reach was lacking these aspects and i would enjoy Halo 4 alot more with these qualities.
Secondly, the Ranking system. I would love to see a combination of Halo 3’s system and Reach’s system. It’s a win/win.
Basically id like two overall playlists, a competitive and a social.
In Competitive, you would be able to achieve a High/True skill much like Halo 3. 1-100 to specify the players skill easier. And in the Social playlist, this trueskill ranking sytem wouldnt apply.
Along with the Highskill system, the Credit system from Reach would apply to both playlists. So, every game in the competitive playlist would result in an earning of credits and (depending on the results of the game)either ranking up/down or staying the same in terms of Highskill. As for the social playlist, You would get a credits earning only, per game.
Personally, i wouldnt want the credits for purchasing Armor, which should be just unlocked, but rather as a form of experience.
Those are my thoughts/ideas on Halo 4 gameplay and ranking system.
TL:DR- I think Halo 4 should have fast gameplay, more snipers on maps, and smaller maps. Aswell as a mix of a 1-100 Highskill and a Credit ranking system.