If you follow the threads for EJ and Maintankadin
View topic - agility+stam gem or dodge+stam gem - Maintankadin
Basically assuming kings which has an expansion on agi if you read thru
8 dodge rating = 0.203% Dodge
8 Agility = 0.169% Dodge, 0.169% Crit, and 17.6 Armor
Agility is about 83.25% as effective as Dodge but it provide threat via crit and armor.
It's all about what they feel they lack in there stats so the peeps doing it are trying to wind up there threat with small impact on there avodiance.
** Remember Warcraft players fail in directions you never thought possible.