I actually had this topic in mind for a few months now but the recent space crunch made me I think I should share some suggestions I had for the site. I also had a few suggestions to improve the functionality of the site too.
As the file number limit will eventually get used up as the site takes on more users I suggest renegotiating the terms on the hosting plan or changing to the different host that dosen't have a limit. Doing both will probably cost more money unless the current host is overpriced so we'll have to either: start charging users with excess pics, create bonus features to entice users to donate, or have ads on the site to offset the added costs.
Gallery:
Add a replace this file feature to lessen the amount of updated pic uploads and to allow us to replace some pics with collages to save space.
Remove all the non english languages in the gallery section as no one ever uses them. If you don't know what I'm talking about there's a dropdown list at the bottom of the gallery section to select the language the site appears in. As this site is geared towards English speakers I suggest removing the other languages to lower the file count.
Add a search comments feature to the gallery. I'm not sure if a mod is a available for Coppermine or not though. Comment search would be great since the comments often had good info in them.
Subalbums, might or might not be possible but it would be a nice feature to have. IE (album My Streetlight Collection with subalbums Powerlite B2217 and GE M-400)
I know some members might not like this but how about restricting uploading blurry and out of focus pics, pics of the same light but at different angles (a collage style pic would work fine for that), eBay screenshots (I suggest starting a thread in the forum with the pic linked to or uploaded somewhere else if you want to discuss about the item), pics with a common light or your own lights (since you can easily retake that shot) at weird angles or not centered.
The site/forum:
Remove any unused features/themes/headers on the site.
Not sure anyone wants to do this, but removing any inactive users on the site. With that I mean users who have registered for the site for at least a year but have never posted or uploaded anything. Users who have made posts and/or uploads should be exempt from this imo. If I were to delete users I would send them a PM explaining this and give them say a week to respond before deleting their account.
Deleting the accounts of known spammers and trolls. Now I know this site dosen't give either often though.
A Wiki for users, could be a good place where we could put restoration tips, ballast info, lamp construction details, date codes etc. The more sensitive info like date codes should be only made visible to registered user who have posted or uploaded pics though.
Anyone else have any comments, suggestions..etc?