His most popular promos are ones where he's attempting to shoot, or breaking some fourth wall BS.
He only did that in the Summer of Punk angle since it was the whole point of it. And only the pipebomb was really a "shoot".
Also, it's not only the contents of it that matter but also the delivery that he does.
But only it wasn't good just at "shoot promos". He was good at promos. Simple as that.