He thought the Dark One wouldn't immediately burst free if the Seals were broken. That was Egwene's concern, and when she pressed him on it, he had no reason to justify that belief. She insisted they be broken only at the last moment, when certain Dreams and Prophesies were met. And that is when they were broken, and the Dark One immediately broke free, only to be caught by Rand using all three powers.

But if Rand had his way and broke the Seals the next day after the meeting at Merrilor, he wouldn't have had Moridin to give him access to vast quantities of the True Power through Callandor. He would have failed.

To me the central theme is, neither the chief male or female protagonists had the correct answer on their own. Any attempts from either side to go it alone would have led to disaster. Only working together while also opposing each other, could they save the world. Just like saidin and saidar work together while opposing each other to drive the Wheel.

I'd say the very core of the story is that gender imbalance is bad for the world. And toxic views of gender and frailty hold Rand back, and only when he accepts that anyone, even a woman he loved, can give up their lives for the greater cause, and that isn't his burden to bear, did he find the mental strength to truly fight the Dark One.