I think we can all agree that the guild halls are pretty drab. One way to address that as well as the abundance of crafting materials is to extend the crafting system to include items to spruce up guild halls. I imagine there would be flooring and wallpaper and various types of furniture/props. The crafted items would follow the theme of the materials used. To start, it would be fine to use existing level textures and models, but could be expanded to include unique styles specifically for guild halls.

It might be better to have the recipes tied to the guild rather than to the individual player to avoid cluttering the regular alchemy window as well as to allow other guildmasters to make use of recipes as well. The guild craft list should be a different tab as well.

I'm open to any suggestions for improvement, but I think that this would be a pretty good incentive for more people to utilize their guild halls as well as increase the usefulness of crafting materials.