I loved the finale for its thematic winding down, and it made the last season work. The rednecks weren't the main bad guys. Walt was the main bad guy, and he built himself up to that point over those five years. After his exile and returning, he tries to make good by going backwards through his progression. He's monstrous when poisoning Lydia, reflecting his behavior for the last two seasons. He's devious and menacing when threatening Gretchen and Elliot, intimidating them but not actually planning to hurt them despite his implications, reflecting his evolution in the middle of the show, when he wanted to be the "man who knocks" but didn't quite cross all of the moral lines he crossed. Finally, he takes care of the rednecks purely with his scientific knowledge, going back to the beginning when he first deals with Tuco by throwing fulminated mercury. In each step, he's pulling back from the monster he became in his techniques to find the part of himself he lost in his journey. And the best part is it happened without him satisfyingly "redeeming" himself, because he couldn't at that point. The only satisfaction he had was that, as he was dying, he did what he could to make what little amends he could and find that part of himself, even though he clearly and absolutely knew at that point he was irredeemable. There was no going back, but he took the steps available to him to at least fall in that direction.