All that is correct for someone who wants to do things the right way and not for erratic admin like his. They are following don't ask for permission, just ask for forgiveness strategy. He did visa ban with a stroke of pen.. why wouldn't he do this 'merit based immigration' in the same way. Courts might eventually stop it for changing laws, but to file a law suit finding legal mistakes in EO is going to take several months by which his election targets would be easily met.
Also, Greg is not always right. I feel he is a bad omen if he's going to lead charge in any of this.. he was the pioneer in filing the lawsuit representing Indians asking USCIS to follow final action date for October 2015 bulletin and lost it very badly. USCIS is still punishing Indians for that by moving dates even slower than what it normally takes