I suggest weekly different story line sub quest, it may draw some new player to play since not all people chasing gear and farm content
IMC may make some
Fairy tale story line
love fiction (like Pajauta love ?)
some math?
or any sub quest that update each week will be good
and change some guild quest reward as well
not something lame but some thing fun or really can help
like guild raid silver earn pop up from 1m to 10m?
or join boruta or giltine each member can get silver or item like magic stone or bless shard when reach certain amount damage, or hitting to get item will be good too.
auto open card album function
anything that can make guild useful to other