I just found the ending with Saul giving himself up really hamfisted and completely out of character for him. It just felt like moralizing for the sake of it.
I think they wanted to do the whole ‘threes’ thing, Walt dies, Jesse escapes, Saul gets arrested.
I do agree Sauls denegration near the end felt out of character to a degree, the guy was a con artist/lawyer his whole life and I dont see him getting that deranged in his old age.
The spark comes from it though, also think about a more structral approach; a socialized health care system would have taken the floor out of Walts meth and drug empire, he would have likely just been a high ranking pharma industry guy.