They added so much in the game, new content every month basically. Here are the list of things you can do.
Solo play:
- Farming dynamis, salvage, limbus, and colonization + lair reive, doing delivery mission for coalition.
- Using trust npc and do sparks quests (think of them as levee, some are repeatable, and you can tackle several at a time - up to 15)
- Crafting: they updated this with crafting kit so you no longer have to hunt materials, up to level 50 I think.
- Pushing yourself to the limit by trying to solo some Skirmish (which needs Key Item to be made). Yes Skirmish 1 and 2 can be soloed. And you can summon trust NPC. I soloed Yorcia Skirmish as Geomancer with Trust NPC, it's fun to see how far you can take certain jobs.
- Walk of Echoes farm: they revised this - so now you can farm the new improved WoE which can drop i-level gears.
Group play:
- You can create capacity points party, this is by definition your "old school merit points" party. You won't find that many people who are interested, but filling a group of 6 is easy, plus you can summon Trust NPC if one of your member left.
- Abyssea party, for when you need to level another job.
- Skirmish, they added brand new one last month, so there are four type of skirmish to do.
- New BCNM: remix of past favorite bcnms, you will need merit points to enter these.
- SKCNM: these drops chapters you need to "updated" your artifact and relic gears.
- Delve: these are now can done with only 6 person.
On top of all that, you can still do the "classic FFXI" if you want to - but with a much improved gameplay - aka easier travel, faster to get xp, and Trust NPC helps a great deal for when people left your group in a sudden. None of the classic element has changed much. The problem, as you have said, not many people are interested. And they did not bother to advertise the game.