I'm not sure that argument goes through

That argument involving the idiot box actually looks like this: Mass media optimizes for outrage. Estimating the importance of the topic by the amount of air time it gets is a mistake.

if the European refugee crisis is important, then aren't Merkel, Obama, and Clinton important?

No. Not in the sense that Merkel, etc. are unimportant, but in the sense that a systemic crisis is not reducible to the importance of whoever happens to be in the office at the moment.

isn't the process by which they enter office important?

If James_Miller wanted to discuss the crisis of the "establishment" center of the mainstream US parties and the rebellions within them, it might have been an interesting topic. But James_Miller want to discuss Donald Trump, personally.

Of course, that's what Donald Trump wants as well X-)