We know Trump made the decision to announce a meeting with North Korea's Kim Jong Un on a whim without any input from anyone, but that's not the whole story.
The Associated Press story on Tillerson's abrupt firing this morning includes this previously unreported detail:
Dismissing Tillerson had been discussed at multiple levels for a long time, said a senior White House official, adding that the North Korea overture and invitation brought more urgency to the decision. Two officials said Trump wanted to have a new team in place ahead of an upcoming meeting with Kim, the North Korean leader.
One senior White House official said that when Trump made the decision to meet with Kim while Tillerson was in Africa, an aide asked if Tillerson should weigh in on the matter. Trump said there was no reason to consult him because no matter what the group decided, Tillerson would be against it, the official said.
Trump didn't simply make the decision without input, he actively rejected the idea of asking for input when prompted. And he could have ultimately made the decision to announce a meeting even if Tillerson dissented, but he didn't even want to hear dissent.
I don't think this bodes well for Tillerson's replacement regardless of who it is. Even if you figure Trump's next choice will be a yes-man, they're going to disagree at some point or another and, when that time comes, nothing they've done for Trump will matter. Trump expects loyalty, but he shows none in return.
Everyone who works with Trump is eventually humiliated. Trump may like Mike Pompeo today, but give it a few months and he won't like him anymore.
It's obviously concerning that Trump is making world-altering decisions with complete disinterest in opposing viewpoints even if they come from his own people.