Hopefully the mythos of Trump as some superior negotiator will be dispelled by, well … let’s just say he reminds me of an employee with a grotesquely inflated resume. Sure, they get the job. At some point they show up for work and display their real qualifications.
A halfway decent negotiator understands the other party’s motivations – that would take some study and some awareness of something outside of yourself. More importantly, though, a good negotiator understands the strengths and weaknesses of their position. Knows what leverage they have – which isn’t to say you cannot negotiate a good deal when you lack leverage. That’s the point of bluffing. But if you are completely unaware of your standing, you don’t have the good sense to bluff.
Let’s be honest here — someone who didn’t think health care would be so complicated, who didn’t realize China didn’t have a whole bunch of sway over North Korea (nor the impetus to use their influence to benefit the US) certainly doesn’t understand what leverage he’s got in negotiating either. And someone whose big experience with taxes is managing to lose an incredible amount of money (probably park the debt somewhere that it won’t be collected) and turn that into a tax-free decade probably isn’t going to enter into the tax reform negotiating with a whole heap of power either.