I would like to outline my viewpoint on the game in general, and the final itself.
Firstly, it doesn't matter how a player wins, and you cannot judge the standard of a match by frame scores. An example will help to illustrate this. Mark Allen played Ryan Day in the 2009 quarter final, and if you looked at the frame scores, you would be forgiven for thinking it was a match of decent quality. Both players are attacking players and were opening the balls up and trying to win frames in one visit. However, they were both missing many chances, before eventually a player would get in and make a big break. The point here is that an 80 break at the end of the frame doesn't compensate for low quality snooker earlier in a frame. An 80 break made off the break off is quality, but an 80 break made after both players have missed 3 chances each isn't quality. Big breaks don't necessarily mean quality snooker.
Quite often you will get a much more high quality match played without many big breaks at all. If 2 players are very good defensively, play a tight game, and have excellent safety, then the quality will not be reflected in the frame scores. There are different ways of playing the game. This is why I get sick of hearing about a player's century break tally. It doesn't matter at all.
Regarding the final, O'Sullivan had a massive advantage going in to the final. Firstly he had won it 5 times before, and Selby hadn't won before, and more importantly O'Sullivan was fresh, whereas Selby was tired. Effectively the tiredness issue gave O'Sullivan at least a 4 frame start. The format had worked in his favour. Playing the first semi, and winning with a session to spare, gave him a full day off. Compare that to Selby, who had played a very tough 16 frames on the day before. It was a mentally draining semi final match, and Selby was visibly tired on finals day.
O'Sullivan had everything in his favour, went 5 frames clear of a fatigued opponent, and couldn't finish the job. He should have won the match on day one of the final. Even though, he was still 3 frames ahead at the end of the first day, and was a big favourite. In short, he was tactically naïve on the second day. He allowed Selby to dictate the match and O'Sullivan didn't have a presence at the table. Erstwhile Selby gained a foothold, and adrenalin kicked in when he realised O'Sullivan was there for the taking.
I think as the match got close O'Sullivan's head wasn't clear as he was probably wondering why he was embroiled in a struggle, which didn't look possible at several stages the previous evening.
It will be difficult for O'Sullivan to eliminate this match from his mind, and he will need to be made of stern stuff to bounce back and have any chance of equalling Hendry's record.
No doubt, the loss was an enormous blow to O'Sullivan's legacy, and he isn't now at an age where it will be easy to lay the ghosts of this defeat to rest.
It will be the biggest challenge of his career.