Can you imagine Mr. Trump sitting through meeting after meeting in the oval office or situation room, listening to all the principals offer their opinions on some issue?
Do you really think he wants to work 12-14 hours a day, 7 days a week except for a few days of golf while under constant scrutiny?
Do you think he's going to read reams of position papers on various issues around the world day after day; even after his 14 hour day in the Oval ends?
How do you think he's going to react when the SS says, sorry Mr. President, it'll take a week to organize your security for your trip to Atlantic City to speak to the Chamber of Commerce about jobs.
Whether you agree with his random thoughts on governing or not -- just as a personality -- do you think this is a guy who is emotionally / constitutionally suited for the constant meetings & discussions as the chief executive of the united States?
What happens the day he gets bored and just wants to have fun? Will Donald be able to be Donald? I don't think he will be able to be true to himself in the Oval Office. It's a gilded cage.
Not being in total control will frustrate him. Although he might enjoy the perceived power, he will not enjoy the job.
Even if Hillary was the only un-trustworthy alternative, one could at least imagine her wonkishness fitting in better.
And there are alternatives.