I think that both theories might be correct in a way regarding whether the Dark One is in, or Outside the Pattern. It is even discussed in the Dragon Reborn while Perrin is traveling with Moiraine and Lan.

I believe that the Pattern is comprised of the essence of the Creator and the Dark One. For it to exist, and function both forces are needed.

Without destruction, nothing would die, leaves would never turn and fall, and nothing would change. However, too much destruction would be annihlistic to the Pattern.

So my theory is at the moment of Creation, the Creator made the Pattern, and took "some" of the Dark One's essence and tied it to the Pattern, but locked the rest of him out, so as not to put too much destruction in. So in essence the Dark One is within and outside the Pattern at the same time. Everytime the Bore is drilled, it allows him to put more of his essence in, in an attempt at breaking free from the Pattern.
I also think that the Dark One wins at the end of the Seventh Age, but by destroying the Pattern, it resets to the First Age, trapping it all over again, and starting the cycle.