Scotus
I usually gauge the importance of something by how hysterical the left reacts.
Also, people who minimize the importance don't understand that a SCOTUS doctrine is a mandate to the entire court system - Not just SCOTUS.
Court are no longer allowed to defer to the agency being challenged. The court has declared that Chevron was a mistake - that courts should have continued to render judgements in cases rather than deferring to agencies.
Most lawsuits relate to gray areas or ambiguous regulatory authority. MQD effectively replaces Chevron with these questions.
1) Does the issue involve a question of major economic or political significance?
2) If yes, the agency must point to clear and specific statutory authority granted by congress.
3) If it can't, the court system will decide and will no longer defer to the agency's interpretation.
4) The assumption is that only congress can make decisions that involve major economic or political significance. Unelected regulatory agencies can't make these decision.