I understand the idea and I think it is interesting, but I am worried that it involves too much politics. Once such a group was established, I would have to make sure that my voice gets heard in that group. That would mean investing time in politics, which I am not keen on.
Of course now the politics is probably mostly "be a big enough company so that Twitter listens to you" - not meant as a complaint, I think Twitter listens to "normal guys" as well, just saying. If you had a special interest, being a big player probably still helps. Björn