To have an entire episode revolving around him and his continuing storyline seemed like merely filler to me. I've never found his character all that interesting, to say the least.
Though at first the idea of this secret character working behind the scenes on the boat was intriguing, despite that it was someone in alliance with Ben. You knew it would be someone familiar, but what a disappointment to find out it was predictable Michael! Then to learn he has wasted his chance with Walt and now has no relationship at all with his son, and has selfishly decided that his only option is to commit suicide. Of course, if you can't kill yourself then the only choice left is to ally yourself with a man who has only completely demeaned and demoralized you to the point where your a shell of the weak man that you once were!
Of course he tries to set off the bomb to early. Did he ever get anything right, ever, without pure dumb-ass luck or through the influence of others? The only thing that actually interested me was the ending. What purpose did Sayid have in betraying Michael so swiftly?!