I've played L5R from 1st edition. Dabbled in the CCG, and i can tell you.
The Taint and the Shadowlands are not needed in most campaigns, except as an existential threat thats somewhere south, and nobody talks about it. Part of it is... as tragic L5R is, its usually considered poor storytelling to have the players forced to retire their characters because they unknowingly ate tainted food, or a maho-tsukai succeeded on a roll to infect them with the taint.
Unless its a game focused on that horror; which can be amazing.