Clark in another post:
9.2: “torghast no longer needed for legendaries”
General Discussion: "why would you give up on Torghast, wasted content 
"
Clark here as part of GD: they’re updating Torghast with a challenge, good.
See that both arguments can coexist… Really great that they updated Torghast with a new mode, it’ll be a shame if they discard Torghast after SL as a side game, new updates or layers with creatures from the new expansion for cosmetics, maybe a change of name. Just like MT should have continue with new bosses each expansion