As an overly broad generalization, Gladwell is at heart a journalist, not a historian (even though he has a bachelor's in history). I enjoy listening to Revisionist history and reading some of his books, because some things in history are revealed by trying to form some kind of narrative (e.g., Historical Materialism), but he's not telling you history. He's forming a story from history. But I think his work is often an excellent stepping off point to real history texts, and it sometimes gets you to think about the second-order effect of things (his episode on Brown v. Board was extremely interesting).
Ironically the Boston Tea Party episode was also the one that broke me and made me bring a lot more grains of salt to my experience of his work. I think it's one of his worst episodes, and one where he tips his hand a little too far and breaks the illusion for anyone who has even casually read any serious works on the period. It's a _piece_ as you said, but it's an incredible oversimplification.