Was Bruce Lee overrated?
Since there's quite a debate about that, specially after Tarantino's movie, let's go a bit deeper.
Was he a great fighter? The answer is he was a good one, but not a great one. This is the only recorded fight. It was a sparring with some students.
To compare, this is how Tarantino portrayed the fight in his movie.
So, was he overrated? No, he wasn't, but the problem is that he's often praised for the wrong reasons. Lee was an extremely creative person, the kind of person that keeps pushing boundaries and following a particular vision. That kind of personality doesn't make great fighters... but it makes great innovators.
In Martial Arts, he was the one that started to integrate different Martial Arts and combine them with western techniques. That seems obvious right now, but it wasn't that obvious until somebody did it. He was a very important figure in the development of modern Mixed Martial Arts. He didn't invent them, but he was the one to lay the foundation stone.
In Movies, again, he was the one that started to integrate real combat movements in Hong Kong martial arts movies. Back in the 70s, martial arts movies were based in Chinese Opera simulated fights. Jackie Chan, for example, was not trained as a martial artist but as an actor for Chinese Opera. I'm not kidding. This is how it looks:
If you see Hong Kong movies from late 60s and early (and even late) 70s, you can notice this. Check Come Drink With Me, or Snake in the Eagle's Shadow. Bruce Lee influenced Hong Kong movies in late 70s and 80s, and because of that, he contributed to modern Western action movies, heavily influenced by Hong Kong action movies from the 70s-80s.
People often praise him as the 'Greatest Fighter'. He wasn't. He could have been a pro (had been something like UFC back in the day), but probably nothing more. However, his vision and his contributions were extremely important. He was some kind of 'Steve Jobs' figure in his field. This one, and no other, it's the reason why he should be praised.