The NBA is about star players. 1-2 super star players make the best teams. There are vary few instances were NBA teams are great with non superstar players. (Hawks) Obviously, you need other players on the team, but when you start with Westbrook and Durant, the team is competing no matter what. Those guys make everyone else better just because of the attention they get.
IN terms of overrating role players; the difference between (to throw examples out) Collison and a Speights isn't that great. Each or expendable. They need a backup big man; the difference between various backup big men on NBA teams just isn't that great (unless the rare instances were you may have Gobert on the bench)
In terms of over rating the Rockets players, they have a bunch of role players that do various things well, but take Harden away from the team and they aren't sniffing the playoffs. Harden allows you to carry a defensive (no offense) point guard. A 3 and D small forward is a perfect fit for him,etc. But, insert an above average shooting guard on the Rockets and they ain't crap.