Mentioning Melo's rebounding brings up another important point.
How good of a rebounder was KG in his prime and how good is Howard? It is hard to say, but Rebound numbers can be misleading. In another thread, someone pointed out that Orlando is not a good rebounding team. This can easily happen if Howard is stealing rebounds from teammates. Look at KG's style of rebounding in the past. Instead of boxing out, he goes to the hoop and tries to grab the ball off of the rim (which he can no longer do well with less ups). This means if his 4 teammates boxed out their man and he didn't box out his, he might have increased the chances of the opponent getting an offensive board. The reason is if he missing the rebound, his man is running free. If he just boxed out his man and missed the board, all of the opponents are boxed out and one of his teammates would grab the ball.
My point is that there are in fact many misleading stats. Since high school, I have felt that RBIs are ridiculously overvalued and tell us almost nothing about the skill of a player. They really should only be used for recording game history. I maintained that Runs Scored, though similarly flawed, is actually marginally more correlated to individual ability since a play that is clearly linked to individual ability -- stealing home or getting home on a throwing error off of a steal attempt is strongly correlated to a skill of that player, not just opportunity.
Nevertheless, stats can help us better understand players. Though many hate basketball +/- here, it seems to be a stat well respected by basketball statheads and it is easy to see why. Using +/- is an attempt to do a controlled experiment. It is very noisy, as are all stats, but it does afford us the ability to compare that player's performance to an actual alternative - how teammates perform with similar lineups.
It is easy for skilled players to look good while leading their teams to losses. Guys like Ben Gordon can get grossly overpaid, while guys like Bosh can be mocked (like last season) despite the reality that he has decided to win instead of showing off. Guys with gaudy stats sometimes need to make a decision: (a) give up the gaudy stats to provide what the team needs to win or (b) continue to do my own thing. Clearly the big 3 on the Celtics agreed to do (a). Bosh clearly chose (a) and Lebron seems to me to have such a high bb IQ that he is naturally team-oriented and has always been willing to do the dirty work. Apart from Melo's efficiency, there is also the doubt many have that he can adjust his game over the course of an entire season to make his team and teammates better. Pierce learned to move more without the ball under Doc. Dirk developed a post game and stopped taking threes. This season, Lebron too has stopped taking 3's and is showing a legitimate post game. Yet Baron Davis has never stopped taking horrible shots. Who will Melo end up like?