I know Pekka is always working to improve this forum running on his own software, so I wouldn't rule out this feature being added. As the saying goes, the best coders are lazy. And implementing this feature would allow the community to maintain the database instead of him having to do it. I can see the concern with the gear db getting cluttered though if it were open to editing. So perhaps he'd want to limit gear db editing to people with over 100 posts, or appoint a mod or two to be in charge of monitoring it and keeping it clean, merging dupes, fixing incorrect info, etc.
My concern with tagging it incorrectly is that not only will the image itself be tagged incorrectly, but then it will show up the gallery for that lens where it doesn't belong. So people looking at a gallery of images for a specific lens will see something that shouldn't be there.
But, perhaps this is my only recourse for the time being since I really want to add this photo to my gallery. Maybe I'll tag it with my UWA 11-24mm lens so it's obvious that it is a misprint and people don't think I somehow pulled a magical 200mm shot. I'll wait a little longer and see if Pekka chimes in on this before I do it though.