How does that matter? LeBron is one of the best all around players and hardly one dimensional. Not to mention for every LeBron at the 4 I can name a ton of undersized 4's that have not done squat when played out of position.
I don't see how that comparison is any indication whatsoever that it would work. I guarantee there are more examples of it not working.
My point is: more or less any style can win in the NBA if you have great players and run that style effectively. Perimeter oriented teams have won the title, so have interior oriented teams. Big teams have won the title, so have small teams.
Look at Melo's shot charts, he's better near the bucket. He plays nearer to the bucket when he's forced to be a PF. Watch USA Basketball, while at the 4 Melo is often dominant. At the 3 he's often a ball stopper who shoots up long 2's.
Melo isn't particularly "under sized" for the 4 in today's NBA. Melo+a center is only going to cost you against a very small number of teams (i.e. Memphis), most nights it'd work out just fine.
Its very frustrating when people rely on tradition instead of actual analysis for where a player should play. Zach Low wrote a piece back in '12 about how Melo is often better at the 4 (but will likely to continue to split time between the 3 and 4):
http://grantland.com/the-triangle/can-carmelo-anthony-really-play-power-forward-and-should-he/
Bleacher Report had a
similar piece
Thats not to say he should NEVER play the 3. But lets say he was on the Suns, that means between your 3 small positions (Dragic, Bledsoe, Melo) you have 0 guys who have been excellent outside shooters over their careers. You're going to get into major spacing issues w/ Melo, Dragic and Bledsoe all wanting to drive from the outside all the time. At the 4 Melo can start lower and allow guys like PJ Tucker to spread the floor w/ corner 3's while playing SF.
If defense is the worry, there's not much that can be done there. Melo is a minus defender no matter where he plays. Like Amare, he's not really interested in defense. Note: in my initial post on this I said it would best if the Suns had a rim protector at the 5 and a swiss army knife Gerald Wallace/Shawn Marion type at the 3 to help make up for Melo on defense.