GM Serper recently posted an article on chess.com with the basic premise that beginners should not open d4, c4, or Nf3, only e4. His point is that new players need to learn to play actively and tactically, and e4 is the way to help them do that.
Here's the article.
http://www.chess.com/article/view/po...l-chess?page=2
Obviously GM Serper is more qualified than me, but there are also many positional e4 openings like you'd find in d4. Different motifs, but still positional nonetheless. I would think a better way to say this is whether a kid wants to play e4 or d4, they need to make sure they're playing sharp lines and not shying away from tactical complications.
Maybe he means that e4 is more instructive from a classical perspective, such as opening lines for pieces, quick development, etc.
What do y'all think?