The Agasha used to have a more distinct identity. In particular, they were part of a samurai/shugenja theme that the Dragon originally had, where the Mirumoto and Agasha would work together far more than shugenja usually would with a Clan's bushi (this also influenced the Mirumoto, which you still see in things like an RPG technique to increase or decrease spell TNs).
But ... the Agasha aren't there anymore, of course. More importantly, at some point they shifted the mechanical depiction of samurai/shugenja synergy over to the Phoenix in the CCG. And what is being done in the CCG heavily drives what's getting depicted in the story. So that aspect faded from the Dragon. The Tamori are, for the most part, basically just defined by being aggressive and militant (they could be defined by the potion thing, but that has never been depicted meaningfully in the CCG so, again, that doesn't take root much).