As far as Trump's foreign policy speech, the general impression is that he struggled with it, had no focus, contradicted himself, and was basically telling a joke without a punchline.
I am no expert on US foreign policy, but isn't that exactly what's been occurring over the past few administrations?.
I'm not sure how much any president has to personally know about global political issues. There is no shortage of experts available to brief them. POTUS certainly needs to understand the critical role the US plays in the world, and be able to make reasoned decisions based on the advice he/she receives.
Trump is quick to act and over-react. When your goal is to make money, you can be almost any type of personality; but holding the most powerful office in the world?. At any rate, I don't think it matters who has the chair, with the perpetual gridlock, not much will get done...good or bad.
ps: ex-speaker John Boehner just referred to Ted Cruz as "Lucifer in the flesh"...oi vey