i'm sure this has been posted before, but i think it would be pretty awesome to have guild costumization in the guild hall. it's so bleak in it sometimes. Maybe use crowns or CE to buy special add-ons to the guild like a survival track or monster training arena (where you could pick the monster from a list and battle it for no reward, but maybe have a in guild highscore on the games) or maybe even a recipe vendor that sells you random recipes based on your tier each day (thus if you have 2 star equipment your get 2 and 3 star recipes). These are just suggestiong i thought would be a lot of fun and make a lot more social activety in the guild instead of focusing always between them.
~post any other ideas anyone can come up with, i'd love to hear them~
I think you should at least get a center piece for giuld halls, like a statue, shrine or portal or something, maybe a globe of the world.