Yes, I've heard Trump speak. And I've read the soundbites that people whose only professional interest seems to be to hunt soundbites collected. And since Trumps loves to speak, and his speech style is very peculiar, there's a lot of soundbites. But I also looked beyond the soundbites, and that is what any person that wants to understand and not just confirm their biases formed on Twitter should do. And if you look beyond the soundbites, Trump is not an idiot (neither are Bush, Obama, Clinton or any other politicians who people who get paid for painting caricatures and monetizing them as clicks painted as idiots). He is somewhat of an opportunist, though this is pretty common among politicians. He also has some very definite agenda - which is not to everybody's liking, of course - and part of this agenda is massive deregulation. If you didn't notice that, you may have been paying too much attention to twitter noise and too little attention to what is actually happening in the government (which, contrary to popular belief, is not ruled by tweets).
I don't think this is true at all. You could say that deregulation is his is goal, but you'd have to ignore his opposition to free trade and immigration, which are every bit as central to his policies as tax cuts, and reigning in the EPA.
His agenda is whatever works for him right now. He throws out policy ideas and sees what sticks. Granted it does take some amount of intelligence to recognize what's working and what's not, but I think his success is mostly a product of iteration and luck--he's been sticking his toes in politics since the late 90s.
But let's say he is fairly intelligent--his ability to believe his own bullshit means that he is just plain wrong about as often as someone who is actually just dumb. Completely ignoring his speaking style, he is just constantly, factually wrong. He's wrong about little details that aren't politically advantageous to lie about.
And like you said, he likes to talk, but nothing he's ever written or spoken about gives me any indication that he has more than a surface level understanding of any topic.