While my knowledge of the D&D is limited, I am aware that there is also Garb's Fight Club as an option for debaters, but it too is inactive. I'm also aware it has a slightly different format to other D&D forums, and to what the Symp could be if it was used, but I think it goes to show that debaters don't really need anywhere else to debate, otherwise they would already be there, like Veteraan said.