Honestly, If they would just make Void Ark 4 Islands, each with trash and one boss. If you join the DF for the 24 man, you do all the bosses linearly. You also have the option to do each island as a 8 man preformed full party with your FC ship; 1 boss plus the trash.

Here's the kicker;

Each island(8man only) has a door unlocked by an item that opens to another boss that's Savage like difficulty level. The items drop from zone events(ex island 1 door is opened by a item that drops like atma did, but only from fates in Sea of Clouds, 1 per character per week; another door is opened from an item is gotten from special maps, etc.) the bosses drop from the same loot table as the regular bosses, plus upgrade items(like gobtwine etc)

Point is, with your fc, you can run 8 bosses a week, do some open world events, it'd make use of all that open space plus give it a more FFXI feel for those in need.