Thanks for the update. I'm not a developer myself at all, but if you need someone to help out in a non-tech manner, please let me know.
I'd like to make some concrete suggestions:
1) Since you're looking for volunteers, why don't you put that on the homepage, or add a page for volunteers at the top (next to Home / Forum / Project / Download etc)?
2) Maybe think about sprucing up your homepage and forums? It's not a problem of performance, since posting and everything seems to be quite fast. It's a matter of appearance and public perception.
3) Delete old parts of the forums and simplify. Make it clean and fresh. I recognize that there's a lot of historical and educational value, whether it be pieces of code or common problems, but Coppermine has matured to the point where the historical and educational values of old posts are nominal.
Anyways, I hope you don't consider my suggestions to be rude or judgmental in any way. I'm obviously a big fan of Coppermine and you have a wonderful legacy, but it seems as if Coppermine has been frozen in appearance and major development since the mid-2000's. My comments were to hopefully encourage you to think about ushering Coppermine into the new and modern web even if it's just a facelift on the website. You're competing with the likes of the new Flickr, Pinterest, Tumblr, not to mention the other free gallery software like Piwigo and the Gallery Project.