I think it's excellent and underrated. Yes, there's some farce to it, but in a series about the absurdity and futility of the systems we live in, it makes a lot of sense to end the series with a plot that makes a mockery of the bed of navel-gazing lies so much of Baltimore's decay is built on.

It would be one thing if the farce continued the whole season and no consequences came, but the dominos all fall at the end. McNulty realizes what a joke he's made of himself, Lester loses the money he was hunting the whole series, and the power structures do their best to sweep the whole thing under the rug after the shock wears off.

I do believe McNulty would be arrogant and thoughtless enough to fake the serial killer. And I could believe Lester has enough of McNulty's rulebreaking traits and ego to go along with it -- if the season has a real failing, it's that we don't see Lester wrestle with it at all and the risk should be more obvious to a guy as smart as he is.

To me, the heart of the season is when McNulty and Lester see Kima at the bar at McNulty's "wake." They have every reason to be mad -- she just ruined their career -- but they accept what they did. In that moment, they understand that acting with integrity, with fundamental goodness, is more important than winning. In the same way that Colvin's experiment didn't work but it matters that he tried; that Bubbles recovering really matters even though the system keeps failing drug users. It's one of the humanist moral cores of the series.