David,
What you're proposing looks very similar to https://www.reddit.com/r/HPPD/ which i imagine is one of the big causes of the decline in activity on this site. The simple true is that Reddit and Facebook have all but replaced forums like this and for good reason. However, that doesn't mean this site is a lost cause. There is a wealth of data, tips, positive stores, and other advice that can be organized and presented in a more useful way. Instead of competing with Reddit and Facebook, make this site into a hub of fact based information on HPPD. Organize all the success stores and positive coping treatments into sections that are easy to read. Have a FAQ about HPPD that addresses the fears we see posted time and time again. Harvest the data from this site into useful and easy to read statistic and info-graphs. Work with the Reddit and Facebook communities and become a resource to them. Have a way for people to easily donate money or time into research. Volunteers could pour through the old forum posts to tag and organize the data. Get some developers to create tools so that people can easily simulate their visual problems and compare them to others. Parter with the Visual Snow initiative as a lot of our symptoms overlap with that condition. This website should become the authority on HPPD, not just another reddit clone.