Question: Since this is a movie solely based on Kung Fu (and not karate), why wasn't this film titled "The Kung Fu Kid"? It seems it would also help separate confusion between this film and the 1984 Karate Kid film.
Answer: There was a comic book titled, "The Kung-Fu Kid," so there were copyright issues.
Titles, names, slogans, and short phrases cannot be copyrighted. In some instances, they can be trademarked.
The original answer does seem suspect without a source, but it should be noted that there was a DC Comics series before the original film called "The Karate Kid" and Columbia Pictures had to get special permission from DC Comics to use the name. All the films even acknowledges the name is used with consent. There definitely could have been a lawsuit if DC Comics didn't want to give permission.
Answer: Even though it's incorrect, "Karate Kid" is the catchier and familiar title, indicating it is a reboot of the popular original series, making it more marketable. It also uses an alliteration that rolls off the tongue easier. "Jurassic Park" is another example of a deliberate misnomer in a movie title. The dinosaurs depicted in that film were from the Late Cretaceous period, millions of years after the Jurassic. "Cretaceous Park" just didn't sound as good.
Answer: While there was discussion to name the film "The Kung Fu Kid", it was ultimately decided to keep the original, and more familiar, title since the film is considered a reboot. Not only is the story line the same, there are many elements from the original film seen in the reboot. And, had Ralph Macchio not turned it down, he would have had a cameo. It should be noted that the title in China is "The Kung Fu Dream" (功夫梦).
Bishop73