Idea for a new game type?
If you mean PvP in GW2, then go to the PvP forums. Any suggestion should be put in the most relevant subforum to get it in front of the eyes of the devs devoted to that subsection of the game. That’s how it’s been since they retired the one-size-fits-all jumbled mess of suggestions by archiving the specific “Suggestions” subforum. Put (Suggestion) or (Idea) in your title to help the devs spot it as such.
If you mean something not GW2 related, I think you’re out of luck as there is not an off-topic area in these forums.
Ah right right. Thanks!