So it's not clear whether this is a bug or intended, but Shuriken Combo is no longer in the spellbook on 8.1. PTR which means that Sub will no longer get the bonus Eviscerate damage in AoE situations, only combo points.
If true, that means that instead of designing bosses differently, what they decided to do is the definition of a knee-jerk reaction and just plain remove the mechanic from the game. So now there will be no reason to bring Sub to Zek'voz or Zul-like bosses because they remove like 70% of what made the spec strong in that specific scenario.