> rank file and employees of these agencies must now rely on the sole interpretation of the law by either the president or the AG instead of themselves. These _were_ independent agencies who handled their own interpretation of the law
At first glance, it seems like it's a positive thing for all members of the executive branch adhere to the same interpretation of the law. It's the definition of "arbitrary and capricious" if one executive agency interprets the same law differently than another. As others have commented, the president or AG's interpretation is still open to judicial review.
Judicial review won't automatically change the president's mind. And according to this order, executive branch employees must only look at the president's decisions, not at what other branches of government say. Even if a judge issues an injunction against some decision by the president, federal employees acting on that judicial order will be fired for not performing their duty to the president.