The warder path, in my mind, first started as a character role, back in 2002/3 when I started writing Cairma. (Though i'm super fuzzy on the dates). A non-channeler running away from big problems punishing herself to be stronger when she felt like the weakest person in the world.
Mentally, a lot of that mentality is there for me. I dislike feeling weak and powerless. That my voice doesn't matter. Warders has a different take on pride, strength and honor. Key things that have nothing to do with the Ajahs, where the Ajahs core of their groups is centered around Sisterhood. Sure, Warders have a 'brotherhood' but there is still that lone-wolf with a pack just a call away. (Yes, i get that its a bit sexist to say, but it really isn't) The psychology behind a brotherhood and a sisterhood are very similar though they function in completely different ways. And the more Dragonmount grew, the more that is generally evident in how Warders function differently than Ajah's, especially when Bonding anyone no longer factored into the formal purpose of the warders.
So, Ajah's serve different purposes and kinda function more as guilds and groups, while the Warders stand more for their philosophy on their outlook then on what they actually enjoy doing as individuals.
That being said, it doesn't apply to ALL ajahs, but if I did a comparison of the Gray and Blue to the Warders, it is more distinctive than, say the Green or Red.