I turn the argument on it's head.
People say that the "poor quality" of the IGS, means people are dissuaded from posting "good rp" on it, and that this IC forum would mean that more "good rp" occurs.
I turn that upside down.
If people are dissuaded from posting RP things onto the IGS, then maybe, the RP things weren't actually that good anyway.
Also: If someone writes articles about their private planet or solar system, on the IGS, then the wider community of EVE players is able to involve themselves, for good or bad.
I'm thinking here of someone saying that e.g. planet III (temperate) of system X is the capital of a civilisation they've set up. Someone organises a fleet of bombers to lob bombs at that planet, and posts screenshots of so doing. That is something that could happen when such things are posted on the IGS. So Be It.
If instead, the articles about Planet III (temperate) of system X are posted on some IC forum that the vast majority of EVE players do not have access to, then, all it is, is a shield against the big meanies. Says that you don't want your private worldbuilding to be interfered with in any way.
I.e. this:
I see no reason to create a slightly larger circlejerk for people that are used to having their RP unchallenged in their own clique.
Masturbation in any shape or form should be done away from the public.
Sorry about the phrasing.
vOv
do whatever.