Juggernaut was around about 3 weeks after artificer went live. It was only posted more recently, and before that there were forumites who wrongly posted melee artys weren't worth a slot in their group, until they saw the video of a group of them basically mocking EE quests..
Not exactly sure how long a really good build takes to go from conception to crawling all over the servers. But if the jug has been around that long then it takes a while on argo apparently because I really didn't start seeing them til earlier this year. where as the moncher has been around for quite a while.