input delay kills the game

[Awful]

You're talking about ping, which is a problem caused by your distance from the server and the quality of your internet connection.
If you can't handle server latency then you could look into upgrading your internet, or find a game whose servers are closer to you.

OP isn't talking about ping he's talking about how everything is server side whereas most MMOs are client side, meaning games like WoW, TERA, SwToR etc, your inputs are based off your own ping whereas FFXIV you're at the mercy of their servers where using abilities like Rescue have a delay when they should be instantaneous.

Same goes for boss moves like Titans line moves/AoEs, threat generation if someone pulls and you pull threat back it isn't a quick snap, the mobs have to turn around, target you, and then run at you, even after playing the game for years I find it annoying still but I can look past it but there's days it absolutely frustrates me.