1. Rand's transformation
This proved that Rand would not turn to evil, arguably the DO and Ishamael's biggest goal since the beginning of the series.

2. Cleansing of saidin
The DO's indisputably worst atrocity that led to the destruction of the 2nd Age, reversed in a few hours.

3. Demise of Semirhage and Mesaana
These two events convinced normal people that they too could battle the Shadow. It was well known that Rand had potentially killed the generals of the Shadow, and there were rumours about Moiraine, but the capture and humiliation of Semirhage, and the defeat of Mesaana by a seemingly young girl allowed people to believe that the highest levels of the Shadow are no more than people and can be defeated by people with a goal.