Well, as far as I'm aware, there's no other activity that relies on a scheduled night. Pretty much all other brackets are either dead or play daily. You're never going to be able to schedule 39s game nights without 'stepping on toes.'
I think anyone interested in 39s is going to have to adapt their revival strategy. Instead of making a 'call to arms' style post and getting a show of hands in favor of activity, they should just grab people for wargames and build a following over the long term, like we did for 29s in MoP. BGs aren't nearly as fun as they used to be, so I think it will be hard to get a lot of people interested in them (enough to revive the bracket, anyway). Skirms/Wargames are easy to get going (they only require a fraction of the people) and are much more flexible in terms of numbers and organization efforts. You don't have to have 20+ people interested to get games going. You can start with as few as 4 and adapt to include as many as 9 before you have to start thinking about BGs.
Speaking on a more personal note, I dislike seeing so little activity in the mid brackets. I would love to support 29s, 39s, and 49s wargames activity if anyone wants to step up to help lead it. I blame everyone flocking to the 20-29 bracket for the lack of activity in the mid brackets. We need to get away from this mindset of instant gratification when it comes to twinking, otherwise we will never have quality games.