Images of schematics should be included in Category:Schematics, as well as the weapon/gear categorizing scheme mentioned above. Even I forget to do it, but remember to add Category:Crafting for images of schematics. Oh, by the way, if it's a normal weapon and it can be crafted, the image doesn't need to have Category:Crafting.
I know this seems daunting and I really should write it down in a formal project page, but I'm really glad you took initiative, so I'm just giving you a quick guide to help you out.
Yeah - recently I've been hacking and slashing away at unused images, though I'm somewhat hesitant on some of them. The thing is, they might've used it as their user avatar, and Wikia doesn't label images used in avatars as used. I could be wrong - not sure if deleting the image would delete the user's avatar, which would look really bad on us.
More than I could write down - in fact, more than I can even think of right now. Most of them are just ideas stolen from other wikis. Others are just things that cross my mind while I'm taking a dump or in the shower, and then forgotten as soon as I wake up in the morning. Though it just reminds me that wikis will always be a work-in-progress - after all, Wikipedia will never be finished, and there is no deadline. So I think I'll live my life, take things one at a time, and not rush anything.
First things first though - I think the new home page is looking pretty good right now. It might be up on the actual main page sometime soon, though I can't make promises.