THIS IS ALL PRE-RELEASE INFO AND IS COMPLETELY SUBJECT TO CHANGE
MAY NOT BE IN FINAL VERSION
This has all been released in the extended editions of gameinformer, IGN, and xbox magazine. The few ecxeptions to this is info that has been discovered via the Halo 4 beta version. I was talking to private church on xbox, and he has acess to all this info, and he asked me to write a reveal post. I believe that he was talking in complete honesty/ (haters gonna hate)
Sprint is default (we all already know)
Customization is still unclear about if you can customize armor, but you can add/remove stuff from your weapons, such as a silencer, extended mags or extended barrel which makes you more accurate. The shotgun can switch to slug rounds, in other words a one shot kill at medium range, about the same range as an assault rifle. You can upgrade your caliber on certain weapons.
Vehicle Maps are HUGE, but vehicles are largely unknown. We only know that there has been MAJOR upgrades to the scorpion and pelican. There is a possible part in the campaign where you can pilot a pelican.
For the create a class, you spawn with one create-a-class that you pick from. These classes include your upgraded weapons and the matching armor abilities of choice. After you die, you have to use default classes, not the ones you made, but you can still pick up amped up weapons from dead players.
There is a completely new revamped look for EVERYTHING!!! It may changed that instead of two precision rifles, there will be only one, for one, two, and three shot bursts all in one gun.
Nothing is known about armor abilities that we don't already know.
This is all he had to say. Also this info may have changed since I got it, or may be a mistake in the first place, so please call me out on it if you know what is true and false in this topic.
thankyou for reading
and like I said, some of this MIGHT be pulled out of the official release
EDIT: and as for evidence as gun customization
If you compare the sound of the BR firing in the first look video to it firing in other newer halo 4 videos, you can drastically tell the difference in sound, like the sound is being muffled, like a silencer is on it