I don't think there are to many forums imho. I've only been here since February, so I can't speak with much authority on the issue, but the way it is set out seems to work alright. For example, I'm no expert on S14 rugby as I rarely get a chance to watch it (no Sky). Same case goes for ML and also Top 14 nowdays for me.
I think having a wide variety of boards means that everyone has a place they feel comfortable speaking about. E.g. I tend to post in the NH forums in concern to rugby simply because I know more of whats going on this side of the equator. I still post in the S14 ones, but not so much as I don't think anything I have to say would be as constructive.
btw, feel free to shoot me down on it, I can take it, i'm a big boy now! :cheers: