As I've said before, the title of "best player in the world" seems to change from season to season for some people (and month to month for others). You can see it in this thread, just by the nature of some of the posts here.
I'm of the opinion that a player's worth should be judged over a period of several seasons, to account for consistency and sustained success. The problem is, many people seem to confuse "best season" with "best player" (see anyone who claimed that Kane or H. Sedin were better than Crosby).
If Crosby has been the most successful player of the last decade, with a combination of more top three Hart finishes/top three Art Ross finishes/Conn Smythe wins/Cup wins, etc., it's a bit disingenuous to break it up into smaller sample sizes. For that reason, I don't even agree with the OP breaking this up season-by-season.
I think that 2008-2010 was the only period of time where Sid's title was challenged. However, I still feel he was better than OV, at that time, and the majority of hockey people thought the same. OV would win every fan poll but people like Scotty Bowman saw Sid as the best, since he was a better driver of offense and played the more valuable position. But, at that point, I don't think there was a wrong answer, as OV was out of this world.
Crosby may not have always played at a level higher than every other player in the NHL, from season to season, but, over the last decade, no one has been better. No one has had higher peaks (see 2010-11) and no one has had more sustained success. No one has won more major individual hardware (Hart/Lindsay/Art Ross/Conn Smythe) than him and no one has had more team success than him (Stanley Cup/Olympics/World Cup).
To me, that's the definition of the best.