(Spoilers) This is a worthy sequel to the original movie and a commercial success. Often sequels repeat what happens in the first movie, but what they did was make something unique, even if it wasn't flawless.
There are some great moments in here. For example the prologue scene ties itself with the first movie and showed how Miyagi can use restraint (which ties to the end), the crane kick was shown to be almost a fluke, the final fight was "to the death" rather than a contest, and most of all this was largely a movie about Miyagi. You could argue he was "the Karate Kid" here.
I'm sure that some may have been upset that it was a different setting, no tournament, very little of cobra kai and that Ali was not the love interest anymore. The good news is that there is a third movie that makes up for some of what people may have wanted. With sequels being very common in our age perhaps writers can take a look at how it can be done.