Sorry to add to your burden, but I am a terrible GM. I'll just be a player.
Also, I like your picture. It confused me when all the Iggies where replaced with the Astra Militarum. It's like suddenly calling all the Sisters of Battle 'Adeptus Soraritas'. It'd confuse a lot of people, even though that is their proper name.
The drop system was never really explained in SAO though. Weither they had procedurely generated weapons that, even with the same name, had different stats, or if they had thousands of weapons that dropped, but duplicates where identical.