I love Smiley's People as well as the BBC version of the Tinker, Tailor, Soldier, Spy. It's one of the smartest spy genre movies ever. I'd definitely think about watching this. But, maybe:

"This makes me want to quit watching. I’m not sure I have the stomach to know a storyline and its characters are going to be abandoned. That’s one of the two main problems with TV as a medium: that it might end too soon or that it might go on for too long."

BTW, I really liked how this article was written.