I don't think it is a problem. Winnipeg drowns most things out but if you remove it, the area will be quite quiet. At most, I would give Winnipeg threads their own subsection (not a local forum, just a section), but I don't think even that is really warranted.
What we could do is institute a system like the building projects section where locations of projects are denoted by a smilie icon that corresponds with the thread. Winnipeg could be
, Regina could be
and Saskatoon could be
, something like that. It would make specific threads easier to spot, perhaps.