Currently the world is "static". Every time I visit Tailfeather, the same NPCs are at their spots, the same bunch of mobs roam the surrounding areas.

Would be nice to have some additional dynamic NPCs. And by "dynamic" I don't mean "random" - that's just as boring.

e.g.

A group of goblin traders at a certain Eorzea time each Eorzea day will travel from CWH to Idllyshire, along the way they might get jumped by bandits or attacked by dragons ... etc.

If players are around to save them in the associated FATEs,
  • they make it to Idllyshire and
  • a vendor there will have the materials he/she needs to make certain items and they will be for sale
else
  • the goblins having lost their goods turn back for the day and
  • the Idllyshire vendor won't have the specific item for sale

This is a very simple example. It would be more interesting when there is a web of relationship between NPCs.

PS: If your reply has the word "convenience" or any of it's derived words in it, I don't want to hear it. Convenience was what made WoW's world as boring as watching paint dry.