Path of Exile is one of the best aRPGs out there. Why doesn't it have it's own thread in the RPG section? I mean, it blows Diablo right out of the water!
Yes now that you mentioned it is strange that probably the best game in that genre doesn't have a section on the forum. You might have to try contacting an admin with your suggestion.
To be honest I never played it, but I have seen videos of the game to me it didn't look that great to me, but maybe it's one of those games that you actually have to play and just can't watch, but as far as being added to the RPG section if it's a popular game I don't see why it does not have it's own section.
Btw when I saw it for the first time it didn't impress me either, but the feeling you get by playing it is a lot different from your first impression.