A lot of rp fc's on Gilgamesh pulled a max exodus about six months to a year ago. Last I knew, most rp was done in the housing wards now.
As for why? Partly due to server wide drama and partly because when rper's designated Gilgamesh as the secondary rp server we didn't know one of the major forums decided to go there as well. Can't remember if it was Reddit, 4chan, or Blue Gartr but it ended up with rpers getting trolled any time they dared to be in public. So it was just easier for a lot of the rp fc's (my old one included) to make the jump to Balmung where we'd be in the majority.
If you do manage to make it on Balmung, explore several different fc's before deciding what one to stick with. And Erik tends to be right, smaller FC's tend to be better. For more than just drama reasons. It's easier to make a better story and make sure everyone's story fits in with lore.
Larger fc's are more likely to have that one person who has to be Louisouix's half miqo'te, half vampire, half voidsent, half elezen daughter running about solving everyone's problems (or causing more) with a wave of a finger.