Well, mainly because if you get crazy and give every single character their own signet, then design gets sloppy and you end up losing signet identity. Which is why I'd advocate for having 2 signets per culture, tops, so that you could either focus on a signet, or on a signet's culture, to build around them. With that in mind, I'd advocate for following the game's first idea (having a signet for each major character in the culture from the movie), and the players view on signets (which I think is actually the more correct one), which is having a signet for "leaders" within the ranks of that culture. So, you'd get either a Denethor/Faramir signet (you could trat Aragorn's either way, depending on the one you might want to have), Éomer/Éowyn signet (probably Éomer), Treebeard signet, Legolas and Elrond/Galadriel signet, Gimli and Gloin/Dain signet, Bilbo signet. I'd have a Sméagol signet, but that'd be it for his culture.