It would be nice to have several themes in rotating galaxies.

SD should stay fixed as a hardcore galaxy but it would become boring rather fast to have SD each month.

So rotate it with another galaxy, let's say good old Triangulum and give this a changing "weird" theme:

a) BotC - Battle of the Countries
Family size: 6
An old idea from the dawn of IC. Teams are put together by countries or regions (for those not represented in enough numbers) and battle it out.

b) Battle of the Specialists: Bankers vs Attackers
2 teams of 20 players fight it out.
Each team has predefined (by the mods/admins) race designs and players can decide which team they want to join.

c) Battle of the Standard Races:
* Partaxians vs Quantams
* Wardancer vs. Camaars

Many more ideas are possible.
Make those themed rounds short, about 4-6 weeks. Every 3 month a new one, may it be Hardcore-SD, BotC, Battle of the ...