This is from a new paper by former Canadian government official Rob McDougall:
the Appellate Body could be given the authority to decide which appeals, or which parts of appeals, to hear (certiorari), based on broadly defined circumstances such as when panel reports risk creating inconsistency, demonstrate evidence of manifest legal error, involve matters of significant public interest or of systemic interest to the trading system, or disputes over imprecise obligations.
People like to feel acknowledged and heard, so I understand why governments want to make sure their arguments to the Appellate Body are addressed. But where the Appellate Body has examined an appellate argument, and is certain that it plans to reject it because it agrees with the panel's reasoning, is there much value in having the Appellate Body go through the same reasoning that the panel did? Would it be enough for the Appellate Body to simply uphold the panel's finding without further comment?