This isn't really something that would be used for local co-op but.
It would be nice to take control of the camera when spectating/dead, it's basically free look but "fog of war" still applies.
I was actually thinking more of physical real world give away items, like flyers of some sort.
But that's a good idea for the future, I've actually talked a lot with kompressor about neat things we can do with fog of war and death but that'll be a ways away.
I've also thought about making left trigger and left bumper pitch your camera freely so you'd be able to adjust it during gameplay, but I'm unsure how useful people would find this.
Edit:
4 Player split screen works,

Going to have to tweak a few things like text size and guis to make this look a bit better though.