You know I am on the same page with you when it comes to Kyrgios. I simply don't understand why so many posters here are blindsided and do not see the weaknesses in his game.
I can't speak for anyone else, but it isn't that I don't recognize that he has weaknesses, it is just that I think his main weakness is...him, his psychology. If he was more psychologically stable and focused, he'd be a top 10 player, at least a prime Berdych/Tsonga, if not a del Potro level talent. That isn't a perfect player, not a big three, but someone who could win multiple big titles, even Slams.
One thing that sets the big three apart, even Andy, is that they have no major weaknesses. They have
weaker aspects of their game relative to other aspects and each other, but they're pretty much good at everything...or were, in their primes. I suppose Andy's serve, especially his second serve, is sub-par, and Rafa has had phases in which his serve was nothing to write home about, and of course Roger's lapses in his second act, and Novak's weird "smash yips," but all relatively minor.
I think the allure of Kyrgios is that he's a dynamic, fun player to watch. He does a few things really, really well - and is capable of some amazing shots. But in a way he fits in a category with someone like Gael Monfils...lots of talent, but just not the necessary champion's mentality that will work on his weaknesses, let alone recognize them. A true champion never rests on his laurels, is always wanting to improve. I don't see that with guys like Monfils or Kyrgios, both of whom could have had better careers if they had wanted it more.
Now how good Kyrgios "could be" if he focused is up for debate. I think at the very least it is clear that his ranking and title history don't adequately represent his upside - like a Monfils, or numerous other players.