DACA was a program created by Executive Order, not legislation. It's entirely an internal Executive Branch policy, not law. It's premised on prosecutorial discretion, i.e., the choice of what to prosecute and what not to prosecute. That's not something which is actually reviewable by the courts. The courts have no say in which cases prosecutors decide to try.
That which is created by Executive Order can always be rescinded by Executive Order. To claim such a thing is unconstitutional is no different from claiming that the ordinary repeal of a law is unconstitutional.
As for the president's "omnipotence," at no point have I ever claimed such a thing. In fact, you'll find that I've argued against Executive fiat vociferously many times. And in fact, having nothing to do with the subject matter of DACA, far from being Presidential omnipotence, it was outside of the President's power to enact it in the first place. If you believe it wasn't, then it's actually you who is far closer to arguing for Presidential omnipotence than I am. DACA needed to be done through legislation, not Executive fiat.
But no matter -- whether or not the Executive Order creating DACA exceeded the President's authority, another Executive Order rescinding it is not.