Sure Trump's personality is flamboyant and loud, but his background is professional deal making and negotiation. Obama by contrast came to us with as a professional social agitator and complainer.
As far as "shooting off one's mouth" goes, I kind of like the way Ronald Reagan "shot off his mouth" against his advisers by saying "Mr Gorbachov, tear down this wall." Some times tough talk is the only sane reasonable thing to do. And flamboyant or not, Trump is not the fool Obama or Jimmy Carter is.
No, he's not. But he's still blurts out things that he has to later qualify.
"They all have to go home" was later modified by "The good ones can come back".
The "no more Muslims" position had to be clarified by "it doesn't apply to American citizens or political or business leaders of Muslim nations".
I could go on. But you get the point. Trump may be an experienced negotiator, but he's not used to having his public word taken as seriously as his private word. Foreign governments, however, will parse every public statement...or aside...for meaning.
For all his linguistic flaws, George W. Bush understood this requirement of the presidency and never said something in public he didn't mean or couldn't back up. I don't doubt he's capable of it, but Trump will have to learn the same kind of self-control.