[Trexmaster]

Yeah, while Pre-GR Fire Breath did deserve the nerf it got, it carried over extremely poorly, its damage being beaten by just about any autohit in the game bar Grenade Launcher, and with the changes to Blazing Shinken, its cinders are outclassed by any soldier who picks up the appropriate elemental badge. (I'm almost positive its cinders don't deal 100% Fire ATK, otherwise it'd be almost okay)

Adding Fire ATK into the equation seems like a no-brainer. (either in the way OP suggested or some other % of Fire ATK).