I don't really see it as a popularity contest. A high member count has never been the goal, to my knowledge.
People who prefer the atmosphere here can use this forum. People who prefer moderation that allows for more robust debate can use Chatsubo, or indeed are welcome to create their own board.
I would tend to agree with Ken, in that I think we have largely achieved the atmosphere that we wanted here, and that it is the moderation to a large degree that enables that along with the willingness of a lot of people in the RP community to participate within that framework.
I don't see how asking people to post constructively and not to attack each other is excessive. Similarly, I think it is reasonable to ask for discussions that create content, rather than having threads where there are two or more sides striving to be 'right' and win.
I understand that some people feel our guidelines are excessively restrictive. Still, I think that we have a reasonable level of activity, and I'm not inclined to support changing something that works.
I don't see much good down the road of trying to please everyone, and I think the forum has been fairly successful as it is. As mentioned above, there are plenty of options for people who want a less strict environment, and few options for those who want the atmosphere that we have here or something similar.