I would like to see a bulletin board feature put within the guild hall.

At the moment, the only function of a guild hall is to escape from the WTS/WTB chatter of the Arcade, and still be able to craft recipes with your guild members.

But, not all guild members are always on at the same time. A bulletin board would allow you to leave notes for your guild members, regarding plans to meet at a certain time to go into the clockworks, or listing materials/recipes you are looking for, or found for someone who is looking for them, etc. I know my guild at the moment believes greatly in collectively helping each member move through the alchemy path of their choice as quickly and easily as possible. We share materials and recipes at will. But it can be a pain trying to make known what you are looking for, or letting someone know you found something for them, as it could be days or more before you are logging in at the same time as them again.