I don't think I agree with you, Dominic. Let me address some points.

It's more than likely that Rand is drawing the True Power through Moridin. I'd personally say its a certainty. The alternative is that the DO can touch anybody in the world, which I disagree with. I think you have to swear allegiance to him to get that connection to his essence, and considering Rand has not done so, it makes sense that he is drawing through Moridin.

Consider RJ's answer to Asmodean's black cords being severed... That was cutting off his protection from the Taint and also cut off his ability, it was not like stilling them. It was cutting the ties that, most important to him, protected him from the taint on saidin, so he could draw saidin all he wanted to and never worry about the taint. But it was also those ties that represented his ability, or the conduits by which he could draw on the True Power. But it was not his ability to draw; it was not the same thing as stilling or severing; it was more like shielding.... Rand has none of these black cords and thus does not have the ability to draw on the TP.

Brandon answered lots of questions regarding this drawing of the TP to destroy Semirhage, namely...

1. 'Did Moridin sense when Rand channeled the True Power through him?' Our 7th RAFO. But he did say, "We don't know if that is what happened or not, and that might or might not have been Moridin's plan all along. We don't have enough info to decide that yet."

2. Brandon was very careful to state that we cannot assume that Rand drew the True Power through the link with Moridin; nor may we assume the opposite. (In other words, we're not supposed to have enough evidence yet to draw a conclusion.)

3. Does Moridin know that Rand drew the True Power through their connection? (Paraphrase) It's always best to assume that Moridin knows a lot more than he's revealed.

Clearly it's the popular and most likely theory. I also don't understand why you insist on needing an evil mind or evil state of mind to draw on the True Power? The Forsaken are evil and can draw the True Power, but correlation is not causation. It's a physical power and if you have the ability to draw on it, you can draw it no matter what your alignment. It makes as much sense as saying that the Forsaken can no longer channel the One Power because they're so unlike the Creator they could never reach the needed state of mind. They have the ability, and they show no lack of aptitude. Besides, Brandon basically answered this...

Brandon said elsewhere that he can still sense it, which means he can still use it, and simply chooses not to.

It doesn't mean that he won't if he discovers that it will protect his circle from a backblast. It may be the ingredient that Lews Therin did not have access to.

Either way, Brandon's final answer gives me a mild sense of satisfaction that something is up regarding Rand and the TP...

Loialson
Can the True Power can be used against the Dark One?
Brandon Sanderson
That is a big RAFO.

My pet theory thus remains that Rand will link with two women whom he trusts, and use saidin and saidar to make a perfect seal. Rand can draw the TP through Moridin... the DO will either not know this (he may still think that Moridin channeled when Semirhage died... even Demandred said he could be remarkably ignorant of outside events), or will be unwilling to cut off the Nae'blis considering he is his only defense outside the Bore. Rand will use the TP to deflect the DO's retaliation, which will most likely kill him, but avoid a taint on saidin and saidar. The Bore will be sealed. There will be a soul swap between Moridin and Rand at the last moment and Moridin will die in Rand's body, and Rand will live on in Moridin's.

But we'll see I guess....