A president has enormous power to do what he wants. Obama has shown that. You don’t need to be a “celebrity” to wield that power.
Also, Trump’s celebrity will not preclude him from needing legislation or amendments to do some of the things he wants to do. If the Democrats and GOPe control Congress, they will not pass what he wants just because he’s a “celebrity.”
I do not see a Ted Cruz as capable of circumventing what will need to be circumvented to achieve ends. I'm not talking about going around the Constitution. I'm talking about very hard ball politics in which you play dirty. People at the IRS don't cooperate with reforms, they get exiled to Scottsbluff, NE. Trump has the personality to do this stuff, and I don't think Cruz does.
Cruz will be a terrific AG in this Trump administration, and I think they've already worked that out.