LTT said that the reason why Saidin was tainted was because something was needed to touch the DO to seal him.

This means that If the DO wanted, he can taint Saidin/Saidar at will if there is a connection.

Assuming that the seal is still strong enough to prevent anything from "Touch"ing the DO, and that he can taint anything right now. Couldn't the DO have tainted Sadin & Saidar back in AOL when he had both male and female forsakens and dread lords at his disposal?

Would have made his take over alot easier.

Also, I don't think that it can be assumed that the DO didn't know he could taint the OP until he was about to be sealed, because, like the creator, he exists out side of time. This means that he would remember from the previous turning of the wheel when he was sealed by the Dragon.

Long story short, I didnt like the explanation of the taint on saidin.