Because most members on our site are big Nintendo fans that will no doubt be getting a Wii. There are already a large amount of Wii topics on the forum, and also, as the Wii is somewhat similar to the DS, we ARE opening a forum category for it, so members on our site that do have one, don't have to go to other sites just to talk about their new Nintendo console.
Well personally I am a Gameboy fan only. By all others means I never liked Ninty and how it behaves. When I first arrived in this forum I was very happy to find a forum for GBA and although I didn't post very much I was always here for the new GBA release roms and for emulation news for it. A Wii forum is totally out of this forum's initial purpose. I would understand a DS or a PSP category but with the Wii directory I totally disagree. Anyway if someone wants to talk for Wii he/she can do it on Other Consoles forum or at least since Wii seems famus open a subdirectory there. Opening 5 subdirectories seems pointless to me.