IMO, the Creator and DO don't really exist in the sense we've been led to believe. I think that they are actually constructs of T'A'R. T'A'R is built upon the collective thought of all sentient beings (specifically humans), and the Creator and Dark One are just manifestations of facets of the collective human psyche.

What we're seeing with Rand is the breakdown of the barrier between perception (T'A'R) and reality. In T'A'R, Perrin saw him as a blinding light, and I think that when Darkfriends see the Light coming from Rand, they are actually seeing it in T'A'R (hence why the guy in Maradon could claw out his eyes yet still see it).

Regarding the TP and OP - I think that channeling is merely the act of imposing one's will upon the world - weaving T'A'R into the real world, if you will. This would mean that the OP is analogous to an individual's choice to act (for good or evil), whereas the TP is what happens when an individual is driven to act by an evil inclination.

Perhaps this is all a bit too metaphysical, but I suspect that at least some of it is valid.