Sometimes I worry about diluting the original purpose of this website by introducing new sections.
Personally, I don't care about adding or not adding a winter camping forum, but I thought I'd act as a voice of conscience.
As I recall, kayaking and off-topic forums were eliminated from the revised version of this site to focus on open canoe tripping. There was even some resistance to freestyle canoeing. Kayaking is clearly more closely related to canoeing than is winter camping. The slippery slope begins when a few people -- quite understandably -- want to discuss their other hobbies.
On the other hand, there have always been a few people here who have in fact discussed winter camping. So, unless the subject is banned, it probably makes no difference whether those posts are organized into a separate forum or not.