Most older cities were designed with playerbases in mind of 100+. Clearly, compared to today's day and age they are a bit overpowered. Especially in Tar Valon it would be more common to see an Aes Sedai mob than a regular town mob, which is curious considering how rare Aes Sedai were...
Therefore, the amount of channeling mobs has been reduced in Tar Valon city, Ruined Keep and Thakan'dar. Tar Valon has a few more different mobs for atmosphere, but Ruined Keep and Thakan'dar had a number of dreadguards replaced with myrddraal.