Well, there's a theory that third part is always the worst. Look, they released it only in Poland, as if they were frightened. But Kao 3 was awesome! Almost. It had a few things I didn't like and it was a bit too short. But still, they could release it worldwide and it would be loved. And they would maybe even continue producing it. Actually, I don't know if Tate still exists... Oh wait, they do... But it seems they've forgotten about Kao. Or they don't want to remember...
Take the third and second game then mix all the positive parts together. Then add some new mechanics, ideas, characters, levels, powers and a new story. Oh! And keep Kao adorable, and BAM! New game that is good.
Yeah but one Polish Friend told me that Tate Interactive doesn't want to make Kao The Kangaroo 4. That's sad.