I disagree about Dragoons giving the ability to give Signet, Sanction, or Sigil out to other players in their party for multiple reasons. For one, Dragoons (and most other Knight classes for that matter) aren't tied to the protection of nations as you say. They all have defining roles that make them what they are, and the defense of a nation isn't that. Dragoons are dragon slayers, and their traits and abilities are aimed towards that end. Just because there were some Dragoons in the past that did defend nations, doesn't mean that it was a definable role for them. If you look at Campaign and all the NPCs involved, there were just as many Warriors, Black Mages, etc that protected nations, so why not give them the ability to give out Signet and the like too? Not to mention, if you want to follow what was established in the story, Blue Mages should be ones to give out Sanction, since the elite soldiers of the Aht Urhgan Empire were the Immortals.
Dragoons originate from Adoulin, and while we don't know much about the area yet, there's nothing saying that they're some nation guarding class or anything. All we know is that they're draketamers. If abilities were given to define their class, it should be for the Dragon slaying aspect, not some notion that they actively defend cities and nations because they're knights.
Secondly, the sources of Signet, Sanction, etc, are so prevalent in their related areas that it's a rather unnecessary thing to give to a job or a few jobs to use.
Third, why make it something that should be automatically bestowed to someone as they come close to those NPCs? There are plenty of reasons someone may not want those effects, so it should be up to the player to choose whether or not he wants it, not given to them automatically because they strayed a bit too close to an NPC.