Assorted suggestions:
1. Storage Bins at Guild Hall. Maybe even a larger, collective spot in addition to the normal storage. Sometimes a guild likes to congregate at the Guild hall - storage access would allow an exchange of items without having to "zone" to Lion's Arch.
2. Customization of Guild halls - This one is "iffy" I realize - because this can be exploited when it comes to GvG battles. So how about cosmetic custom features - such as building style, custom color/emblems, or even changing time of day/weather.
3. Display of Guild Initials on main hall +/- banner in a tasteful fashion.
