Trump is charismatic in a carnival barker kind of way. I suppose he developed that style from his multitude of appearances on the Howard Stern show, or was it from his Miss America tenure, or more likely his connection to pro-wrestling.
As far as speech making capability, Trump is often hard to listen to. He repeats almost every thought, which is a very annoying trait, and is prone to not finishing sentences. That can limit his effectiveness in getting important points across.
Perhaps, that is why he relies on insults and invective so frequently. It covers for his inability to distill critical facts and deliver them coherently.
Only idiot leaders like Jimmy Carter get involved in details. When I worked in a Billion Dollar sales outfit, privately owned company, the owner never got involved in details. He was good at strategic goals and setting direction for future business. Trump has been a CEO making million times more money than pipsqueaks who never made twice the national average. Those pipsqueaks have no clue what made Trump achieve more conservative results than last 10 republican presidents combined.