A statement like this presumes that quantity of traffic is the only reason one might split a forum.
And this is not likely to be a problem for separate Mac Pro forums for quite some time.
On the other hand, the documented frustration involved in sifting through all the old Mac Pro articles is making me (and presumably others) look elsewhere for new Mac Pro information and discussion. That should be of interest to MacRumors folks.
A.
Well let your frustration be known, and if there is enough feedback sharing your opinion then things may change. But since we're going on a year now with both models I don't think things are going to change. Honestly, it's not hard to wade through the forum.