Kung Fu Panda 4 is a good, enjoyable movie, however it's without a doubt the weakest of the franchise.
I think the main issue with the film is the fact the furious five are not in it, which is just a terrible and very strange decision. It's explained in the film they're all on separate missions. I don't understand why they thought the audience would be ok with the furious five suddenly not appearing. I think the the furious five being main characters, alone, would make the movie and peoples opinions alot better. They do make a brief appearance at the end of the film, during the credits, which was actually a really nice surprise but they don't speak.
The villain of the movie, the Chameleon, is pretty good, the concept of her shape shifting is really cool and interesting to watch and it's very well animated but she is definitely the least threatening, memorable and interesting villain of the franchise, which is surprising considering she can turn into any powerful master she wants.
The next thing to talk about is the new main character, Zhen, played by Akwfina, who becomes Po's successor. She is a good character and she has a great character arc throughout the film. Her and Po's friendship grows nicely but she doesn't feel like the right character to be the new dragon warrior. I get they wanted to do something different and interesting but the audience are very happy with Po continuing to be the new dragon warrior. The main problem with Zhen is she's voiced by Akwfina of all people. There's nothing wrong with her performance or her as a person but it's just her voice is very distracting. Everytime Zhen speaks all you hear and see is Akwfina. I must say though a secret is revealed about Zhen and the villain which was an unexpected element that genuinely shocked me.
The minor side characters in the city aren't good or memorable. It feels like they were trying to fill out the cast, characters and world.
Also it feels like they're trying but mostly failing to capture the humour and magic of the the first three movies.
Now when it comes to the positives, there's plenty of Master Shifu and he's still his awesome Shifu self. Giving plenty of inspirational, well written quotes.
Both of Po's dads get their own side plot so we get lots of them together. The reason for their inclusion kinda feels cheap just to have them in the film but it's still really great to see them both together.
Also, though not as good and memorable as the other three, the action is still great.
But easily the best thing about the movie is the return of all the villains. Though it would have been cooler if they were more involved in the story and Shen and Kai got some dialogue and action scenes, it was still really exciting and really cool seeing them again, especially all together, felt kinda surreal actually. Tai Lung got alot of dialogue too, which was good.
The villains however didn't feel consistent with their past appearances. They don't really act in character. These are villains that have alll fought and been defeated by Po. They have all tried to kill him and are all so evil yet they all don't even try to fight Po given the opportunity. They accept to go back to the spirit realm and even willingly bow down to Po in respect to him. There is no way any of the villains would do any of these things.
So i'd say I do definitely still recommend Kung Fu Panda 4, there's still lots to enjoy, specifically in the third act but it certainly has issues and really lacks the magic and flair that Kung Fu Panda 1, 2 & 3 have.