The point of the show wasn't for Hank to find Walt out. The point of the show was to see Walt go from mild mannered teacher to drug king pin. And at the point where season 4 ended, he had killed multiple people, poisoned a kid, dragged his whole family into it, and took out the head of the empire. He won. He broke bad. THAT's the point of the series. The point wasn't about him getting caught or who was the one to catch him.
Ultimately, for me, season 4 was the apex for Walt. He had crossed the morality line hundred times, was bringing bombs into a hospital where a kid ws dying because he poisoned him so he could use his bomb on someone else, then set the bomb off at a nursing home that could have killed any number of more innocent people. Season 5 just served to reinforce that he was a bad guy, at times where he's comically evil. From Mr. CHIPS to Scarface is the phrase Vince Gilligan always used to describe the show. Well, season 5 is to Breaking Bad as Scarface The World Is Yours is to Scarface. A fun romp in the world, but ultimately just repeating itself and doing nothing to change the point that was already made.