How about this:
Everyone spawns with the only mid-range head shot capable weapon in the game. Make it powerful so you can actually RELY on it in most situations. Balance the weapons in the game around this weapon. Everything gets A LOT MORE POWERFUL. When this happens most other weapons become situational. Power weapons are just that, powerful. They are no longer free kills because, everyone spawns with a powerful weapon. They reward those who fought for and control that area of the map.
Remove dual wielding, useless/clone weapons. Putting more weapons in the Halo sandbox will only nerf existing weapons, making them less reliable and more frustrating. Having a smaller sandbox allows for powerful consistent weaponry and game play.
Do not include equipment... unless its carefully though out and placed on maps where ABSOLUTELY needed. Getting ganked from your deserved kill by the victim pressing X and vigorously t-bagging isn't very fun, especially when they don't even know where you are.
Maps should be generally arena sized. (Don't get me wrong, BTB maps are awesome and will be included.) Reward the thinkers instead of campers. Promote movement. Change the weapon spawn timers. Instead of a set time counting down when you pick up the weapon, make that timer start at the beginning of the match. This gives both teams an equal opportunity at ALL power items.
Too lazy to think of more. But you get the idea. Stop noobing the living -blam!- out of this series.