Like topic says, right now it's very hard to find people interested in doing coils so you spend enormous amounts of time in df queues (even for practice purpose) or in pf (even when going unsyced)
Coils of Bahamut are very fun and interesting raids, I still prefer them much more to what we have now (Thordan, Alexander Savage). Honestly, i can't imagine this game story to be complete without going through them, as plot is really interesting and fills the gaps in regards of Eorzea past. Yet since all the rewards you can possibly obtain from there are long obsolete, people don't wanna go in there even unsynced. Right now my alt character has trouble going through them, since barely anything pops in DF and I wait in pf for someone to join for ages.
What I'm thinking, is that some kind of additional reward (maybe weekly or some essential stuff for new relic) would spur people in going there for achieving their goals while helping other to fulfill their own. Old content should never be forsaken, but in order for it to be alive you gotta motivate masses in doing them. I'm just after fun and thrills here, but many others will never do something old just for that, so they need some trinkets in addition to that
Same can be said about Crystal Tower raids. While I always hated them and been doing them as a weekly chore before HW, it's still unfair that it will be forsaken and forgotten by everyone, except newcomers, who will find themselves in trouble clearing this content