The real tragedy to lose would be r/ffxivdiscussion , where people actually talk about encounters and game systems/mechanics. That one's very forum-esque and doesn't translate to Discord well at all.
I was bored the other day and went looking for that sort of section on the official forums, was very surprised to see it doesn't exist. There's subforums for lore discussion and dungeon discussion (lol), but not a subforums for raid discussion or high-end duties in general.