Of which you have zero evidence. Nynaeve is almost as useless as a channeler can be and she defeated Moghedien. Verin managed to stand against inverted/reversed weaves as the Cleansing. And don't forget Rand who has defeated numerous Forsaken, including Asmodean using almost no training. It seems that the difference between a hugely skilled channeler and moderately trained one isn't that big. Merean vs Moiraine is a good example of how training can influence a battle.