Interface where you can create a public parties and all the city can see and join it. Create with a name, example: "Mass garden party", "Raid party", "Raid T3 party" etc...
This will resolve the spam in blue chat problem about "who have mas" or "any mass party"? And will make the parties system more friendly.
I had this same idea. It could be another tab in the "Party" window -- showing existing public parties, current number of members, info message (created/updated by Party Leader), and a "JOIN" button. There would need to be a way for the Party Leader to make their current party "public" -- or not -- as desired. (Less easy and probably not necessary to make it "un-public" after the fact.) Optionally, allow Party Leader to change the message to keep the news current. For EVENTs (e.g,. Crusade, CTR), the server could automatically create the party 30 minutes before the event starts. So no more blue-chat-spamming, no more confusion of multiple parties, etc..
Could be an always active party (doesn't care it have 0 members) you can join using a command. /joinparty garden or /joinparty mass, /joinparty raid, etc...