As a remake, it has to replicate the key story elements:
- young kid is bullied by other kids who happen to be trained in martial art
- the kid is rescued by a handyman/caretaker who exhibits great martial arts skill
- the bullies are trained by a teacher who has no honour or sense of sportsmanship
- the handyman challenges the bad teacher in a martial arts tournament: his protégé against the bullies
- the handyman is himself a broken man, damaged by personal tragedy
- the kid undergoes very unorthodox training -- in the original film, it was the iconic "wax on, wax off" methodology
- in the tournament finals, the kid is seriously injured but makes a phenomenal comeback -- in the original film, it was with the iconic one-legged crane stance
There are other differences besides the "wax on, wax off" and crane stance elements. The story takes place in Beijing and the martial art is not karate but kung fu. (In fact, internationally the movie is titled "The Kung Fu Kid.")
The movie is part travelogue, as we get to see some fabulous parts of China. Some parts are not even normally accessible by tourists. Having been to China myself, I can attest to the authenticity of the film, the landscape, the culture, the sights. It felt "right" to me.
Jackie Chan gives the finest dramatic performance of his career. I liked him a lot more than Pat Morita.
Jaden Smith is the real find here. He is head and shoulders better than Ralph Macchio ever was. Between Smith and Chan, they made the film what it is.
In short, I liked the remake considerably more than the original, which I also liked. Needless to say, I give it a hearty Thumbs Up.