I just though of this awesome idea of theater 2.0 or a mode to make Machinima.
It could either be a new mode or just be Theater 2.0, it’s not just a replay mode but you can actully play in it and rewind instantly or go 3rd person.
You get accses to all the armor so you can fully expoit the new armor’s in Halo 4.
An idea is to have ragdoll/corpses and paint blood on walls and such.
Begin able to use slo-mo and not how it is now.
Maybe even motion capture with use of kinect.
There you can have lower weapon online and option for no weapon.
Voice capture over live.
And begin able to upload it instantly to Machinima or others.
Having scenes and adding them all together at the end.
Discuss, i will add more good ideas from you and if i come up with more myself.