So I didn't read everything, because holy verbose; but...
This community is not a development/programming community, so on the subject of those board changes and even web development.. that isn't who your members are or have ever been. The RSPS community has been 2% innovative programmers and 98% implementers (i.e. copy & paste scripts, "re-writing" code from other release protocols). You might disagree with me and that's fine, but I even look at what I know now versus back when I was involved, and I was a fool. The content you are going to get in those sections is going to be weak and inactive. If anything you should just cut any of the extra boards that strive away from your core audience.
You want a vibrantly active community, make a plan for a new community. RuneLocus isn't a minecraft server, a programming forums, or any other variant. It's RSPS. Always has been, should always be. If the community of RSPS is dying, that's a fact you just can't change.