I see wud's point, for sure, in that there are aspects of studio photography that go beyond just those aspects of doing portraits and how to light things, and having them all in one place would be nice for folks wanting to work on those things.
That said, if there were a Studio forum in addition to the current structure it would make it difficult to figure out where you wanted to post something about portrait lighting in the studio as there are now 3 places where you can post it, and 3 places you need to search to look for something.
I thought, at one time, there was a tagging system available here (I remember someone tagging one of my posts at one time and being surprised by it), but while I can see Tags in the Search function I can't find anywhere to add them? Not that anyone would think to use it, but perhaps tagging posts with "studio" or whatever other related tag is appropriate would help?