2010 Petacchi's train was... Danilo Hondo.When was the last time that happened? 2010 Petachi?
If you want to argue that because he successfully derailed the HTC train of pain on more than one occasion, that made him the best leadout rider, I'd quite likely be with you (I believe I made this argument a few times at the time, since at the time received wisdom was that Renshaw was the best leadout in the world because of being the last one to launch Cav, but I felt he was the final piece of the puzzle in a full well-oiled machine, whereas Hondo and Petacchi would be three or four riders apart, on opposite sides of the bunch, and then miraculously appear together in just the perfect position at just the right time.
2011 Cav was far more the example of the propaganda for the sprinter with the best train. Coincidentally, that was the year that the points system was changed, because it was considered silly that Cav had won 6 stages to Hushovd's 1 in 2009, and 5 stages to Petacchi's 2 in 2010, and still not won a maillot vert, so the system - which already paid sprint stages more importance than intermediate or mountain stages - was revamped to make it even more sprint-weighted.
This also had the separate benefit that the UCI rule penalised missing the time cut by the equivalent points for that stage - meaning that with the new increased value of a sprint stage, missing the time cut not once but twice was the equivalent of a single sprint win as a mountain stage win was worth barely half (55.55%) that of a flat stage.
The high value of the intermediate sprint made it very suitable for Sagan for a long time because he could get a decent enough amount of points in the flat sprints, but he could reach intermediate sprints in breaks in medium and high mountain stages where his rivals couldn't get anything.
Which, ironically, was how Thor Hushovd won the maillot vert in 2009 and caused people to complain that the system didn't benefit the best sprinters enough.