I think this might be a case of which comes first. I think with the default sorting being upvotes or whatever you wish to call it will make recruitment posts disappear, resulting in people reposting them every day at least to get some visibility. So the question is, if the current sorting discourages posting threads like that because of the reason I stated, then you will end up not seeing many recruitment posts, making it appear as though the need is low, when in reality the people using it are just aware of the difficulties and don't bother. I think it might be better to make the board, see how much use it gets after a period of time, then remove it if you feel it is underutilized. This way you can see the real use it gets because there won't be anyone discouraged by the new sorting methods. (I realize you can change sort order, but I don't think many people will do that in Misc. or whatever simply in hopes that recruitment posts will be on top. Most users leave things as they are default). I think putting the onus of board creation on users who may think the board is going to be made when the designers have all the cards when it comes to board creation and removal is slightly unfair.
On an unrelated note, is there going to be some sorting, alphabetical or otherwise, of the board navigation list? It's really poking at my OCD-ness. Also, GD is pretty non-descript for people who aren't typically members of the GD community, maybe rename to General Discussion? :P
Also, make the board or I'll have to give you a math test for real. I mean it. Don't test me (hue).