Not necessarily ... when you start looking at the women who were at Dumai's Wells, the majority of them are on the weaker side for Aes Sedai (Sashalle aside). False Dragon's like Yurian on a ++5 or ++6 level would have still needed several weak Sisters to hold them with absolute certainty. ++6 would have seemed massively powerful 1000 years after the Breaking once men who could channel became more rare in general (or were Gentled long before they hit their potential). Especially since we've only got one named Aes Sedai (Carhaigan) who was a top-tier woman prior to Nynaeve. Mabriam was a level 9 during the Compact Years and she was clearly an important figure comparatively a ++5/6 man would seem massively powerful, even more so when you consider that Semirhage at Level 1 was held by 3 (including Daigian). Realistically any 6 Aes Sedai level women should be more than a match for any single channeler, despite what's said in the books about Logain nearly breaking free. Rand only managed to free himself when it was down to 3 women.