FFXIAH.com

These NPCs are always going to work better for some than others because people do different things in the game. Whether it's a guild, an auction house, your favorite homepoint, or the NPC that warps you to and from Whitegate, everyone is going to be at a different point in the game. No matter what position these NPCs are in, it'll favor some more than others. And if a person's playing habits change, that may evolve as well. The fact is, no matter where the NPCs are in the entire city, it is more convenient to use them than to get to the outposts by either walking, Chocobo, Teleport, or any combination thereof. They could stick the NPC in the basement of Heaven's Tower, and it's still more convenient than the alternative. Unless you have your HP set at an outpost and you can just Warp to it, there's nothing faster. Considering how many years SE made people Bazaar in Batallia Downs or go to their home nation to use the NPC to teleport to Whitegate, I doubt they are concerned with a 60 second inconvenience regarding the placement of Signet NPCs.

I think SE was more interested in making the NPC easier to find. They aren't concerned with how long it takes you to run across town.