I definitely don't disagree that a reverse sidecut ski would be awesome. And that for many people's purposes, the EPs are too soft, but I think you really have to look at what the kid wants.
Any ski out there that isn't a price point ski, and even most of those for that matter, are great skis. Anything that is wide underfoot is going to be a blast in the pow compared to what used to be available, so it really matters what you want the ski for.
ARGs are an extremely beefy ski, especially underfoot, but even in the tip and tail. They are a great ski for someone who is looking to charge more often than not. Again, they are a great pow ski, but not necessarily what he seems to be looking for.
When he said he is a "soulful skier" who likes slash turns in pow, it is obvious that he is more about having fun in the pow than killing some huge line, or straight lining a chute. I think the reason that everyone is recommending the EP Pro is because it just fits what he is looking for.
Having owned the EP pro for a while, I wholeheartedly understand that it is not for hardly anyone, and I mean that, almost no one fits this ski from what they say they like to do. Once they get it, they may end up becoming that kind of skier, but working at EVO for a year, I sold 1 pair of EP Pros, even though I owned them (quite the opposite of most people in a shop, who only sell the skis they own).
So I don't disagree with you that the ARGs are an amazing ski with an awesome concept, it just doesn't fit what he says he likes to do.