THEORY: The Tao Trio have some relation to three worlds...

[Instrutilus]

Bare with me, here. Now, as far as we know, there are three 'worlds', the Pokémon Universe, the Dream World and the Distortion World. Each has a strange resemblence to the Tao Dragon Trio:

Reshiram is white and dream-like in appearance, while the Dream World is bright and literally a dream.

Zekrom is dark, but not evil, and has a funny, distorted look about it, while the Distortion World is described in the name and is clearly dark but not evil.

Kyurem, meanwhile, is cold and empty. The world is oft described as a cold one, while the space between planets is empty. It is also neither light nor dark, but a mixture of both.

Before you say that they never created the worlds, I never suggested they did: they could just be representatives or the Dream and Distortion Worlds could be a source of power for them, over the real world which Kyurem/the original Dragon draws its power from. Or perhaps it's just me being silly =P

 

[The Outrage]

Problem with that is there are more than three worlds. There's the dimension Arceus and the other two Creation dragons reside in (and we can see their portals in Platinum if you don't jump into the Distortion World right away), and there's also the Unown's world.

Anyway, what you're suggesting just seem like vague relations.

One can argue Kyurem to be Distortion because of its mangled body. Kyurem also isn't a combination of light and dark, the way its played out right now seems like the absence of anything and the Distortion world is a world where our laws of physics are absent.

I really don't see what makes Reshiram more dream-like than the other two dragons either.

Vague physical similarities aren't really something I'd use to conclude what you had concluded, so I'm going to go with you 'being silly'

It's also nice to see theories again.