Depends on the point of view - compared to other games this game still has a moderate population, though we can probably expect another server merge in the coming future, at least for EU.
If we talk about open world PVE, then yes this aspect is dead. World bosses are a thing of the past, they even took out Black Wyrm.
Open world pvp? - Yes this too, the game can´t handle these kinds of large scale battles with the current engine and 1 shot game-system
=> even if both players have the same gear, it fails on the ping or balance of both classes
6v6? - More than dead, it doesn´t exist for the vast majority of gamers. Be it Arena-players, who are only interested in PVP, but are capped behind gear that is only available through PVE or players, who can´t catch up, even through intensive PVE sessions up to 6-9 hours a day, unless they invest cash into this game.
PVP? - Though it is gear equalized, it fails on the class balance, since the beginning of this game and the release of some classes it remained rigid, with summoner being the bottom class from the beginning to the end.
PVE? - Though 1,1k AP is not needed for alot of dungeons, the urge to clear dungeons and kill bosses without regard to mechanics still remains. Being trapped in a run and wasting time, due to the vast gap between many players and fast paces patches, turned this game into a race
Raid? - Capped behind gold, gear, ping, class balance, dps & class compositions(12 Members: 2 WL, 2 BB, 2 Gunner(reset/high dps class), 1 Tank, 2 6s PT iframes, 2 Healing classes(SF/SUM), 1 w/e