I'm a Kobe fan so I admit bias but I do want to respond to this comment.
The 2008 and 2004 Finals and game 7 against Phoenix diminished Kobe's rep as a leader and go-to guy, but not as a "closer," which is the topic of the thread.
The second half of game 7 of that 2006 Phoenix series didn't prove he wasn't a great closer. It proved he was a whining, pouting little crybaby and a quitter. He was actually having a very good game before he decided to quit.
The 2004 NBA Finals didn't prove Kobe wasn't a great closer either. It proved he was a selfish egomaniac. There was only really one close game in those five Finals games, and Kobe actually did play really well and closed out the game great in that one close game (game 2).
In last year's NBA Finals, he wasn't great, but similar to the Detroit Finals, really only in game 4 was Kobe not a great closer. In the other games, the scores were either not close late in the fourth quarter or Kobe actually played well.
There's a lot to criticize about Kobe, including being over-hyped as a closer, but more pertinent criticisms involve his selfishness, his ego, and his failures as a team leader. Yes, he's still overrated as a closer. But, he's still a very, very good closer and his determination, mental approach, cold blooded at ude, and ability to maximize his skills late in close games have generally yielded positive results. He's not close to perfect at closing out games, but he's still currently one of the best closers in the league.