Hmm... as a rabid Zutara fan (lol) I do like the idea, since I love seeing so many wonderful entries. I would worry about the timing, though. Younger contributors might be busy with school. I like having summer Zutara week because I'm not in school and have the time to write more. I'm in college and have a good bit of December off, but that might not be the case for other students, especially ones in high school. So, I could go either way, really. I love Zutara Week and could totally stand to have it more than just once a year, but then again participation might not be all that great depending on when the week was.
Anyways, thanks for asking, and good luck with whatever you decide to do!