We need hard areas, Open world dungeons. The games world is way too easy and pretty much too safe. For such a dangerous world, I literally feel no threat walking around the world. Isn't the world of Final Fantasy suppost to be interesting, dangerous? I don't think so, it is a total joke.

Introduce Locked Encounters
Locked Encounters means outside players cannot heal or damage the boss you are attacking until everyone from that group is slain or dies.

Introduce Mobs that cannot be Zerged.
If you challenge a mob with more then what is required, it will either wipe your group quickly depending on the mob or you can kill it: You just will not get anything from it, no chest, no nothing. Make it so mobs if you challenge them with more then what is required get super buffed, or call for help.

"Ah! A challenge worthy of me!"
"There are too many! Help! (calls entire zone.)"

Introduce Challenging Solo bosses around the world, which can be soloed by some classes or 3 manned.

And furthermore, give zones wandering non-boss NPCs and more interesting mechanics like getting stronger the more they have attacking a player, debuffing players or sending them away to actidently pull more, knock backing players into other npcs. Ect ect.

This world is rotting, it ... needs more challenge!