People fall into the same trap with Melo as they did with Webber - focusing on the glaring weakness rather than the multitude of strengths.
OK, Melo can't or won't defend much. Ergo he is not as good as LeBron, who plays both ends. Sure, that's an easy talking point. You will win every barroom argument with that one. But try to keep it in perspective. Damn near everyone in the NBA has these weaknesses, and every good coach or GM knows how to work around them. Example: Steve Nash. The Suns aren't going to start Goran Dragovic over Steve Nash because he is a better defender. Sure, if they could get Chris Paul or Rondo, they'd consider trading Nash. But there aren't many players that would be significant improvements, and what they'd have to give up to get that player would likely weaken them at 2 or 3 other spots. There is very little point in all these attempts to grade players vs some theoretical perfect player. If Jordan was playing today, there would be people who bitched about his long-range shooting, I guarantee. Who cares, he won games! He was playing beside Kerr, Pippen and Kukoc, some of the all-time great 3pt shooters! That's how you need to approach someone like Melo.