Romi some of the stuff you have written here is freaking genius! (no pun intended)
I actually really like your call to action idea. Ideally it wouldn't be at the bottom of the tabs though as most people likely fail scrolling even that far.
1. We have to get people to engage with the page like you're saying by adding call to action improvements somewhere throughout the page. Perhaps even remove the banner at the top and make it a pop up (idk if that will be overtly annoying etc)
2. The separation of the comments from discussion is an interesting idea, only thing I fear is that since we already have only a small amount of comments, further breaking that up a bit more will fragment the engagement of the page.
But you have some really solid points, I think one thing we need to do that you caught is make sure people can feel like they can improve these pages and that the pages do need improving. Simply saying THE SITE'S A WIKI in the banner is not enough it seems.