Personally I feel Isaak was the best "villain" (if you can call him that in the end) character of all the seasons. I was really feeling sorry for him nearer to the end and I wanted him to survive , he would have made a great companion to go alongside Dex, but he frustratingly shut him out (Just like he did to Miguel).
Also, I loved the last scene with Isaak on the boat; it felt like you connected and was (without sounding like a softy/sady) kinda heart warming, it was played out very well. Just like the conversation in the bar last episode. I have to say, two of the best scenes in the season.