In order to build a Championship team a number of goals need to be accomplished:
1) Star Power: Right now Golden State has two players that I would call Superstars (Durant and Curry) and two other players that I would call Stars (Thompson and Green). There is no substitute for talent - you need to have at least one Superstar and 2 Stars to have any chance at a Championship.
2) Depth: In my opinion, Cleveland had only three players that could be classified as Superstars or Stars (LeBron, Kyrie, and Love). But perhaps more importantly, I believe the Cavs lacked the necessary depth to defeat Golden State which had a very strong bench with good role players.
3) Balance: A Championship team must have a balanced roster. Too many good players at the same position usually does not work. This is the case because both players want to start at their preferred position and the player who doesn't start is often unwilling to accept a bench role. Asking a player to play outside of his natural position fails to maximize the player's talent. It is difficult enough in the NBA for a player to excel at the player's preferred position. This doesn't mean that a player can't develop his games to add more variety or play some minutes outside of his natural position.
4) Three Point Shooting: Teams in the league have figured out over the course of the entire game, the difference between a three point basket and a two point basket really adds up. A much greater percentage of players are starting to make a high enough percentage of three point baskets to make them more valuable than quality low post players. A team absolutely needs three point shooting from a few different players to be a Championship team. It is a fallacy, however, to say that 3 point shooting must come from a "stretch four." There is nothing wrong with a "stretch four," but very few of these players actually exist. Many excellent teams get much of their 3 point shooting from their point guard (Curry), shooting guard (Thompson) or small forward (Durant).
5) Defense: A Championship team needs to play good team defense and players must have the skills to be good defensive players - it is about effort, coaching, and talent. All three of these elements are necessary to build a team with a Championship caliber defense.
6) Good Coaching of Coachable Players: A Championship team needs a coach who is able to motivate his players, put them in a position to succeed, keep the team unified, and have a good game plan for the opponent. The coaching staff must also develop its players over time. The players need to buy into the team concept and accept coaching. There will alway be some problems. I don't believe Michael Jordan was a fan of the triangle offense, but he accepted it.
7) Teamwork: Unselfish play is important. Players must know their roles and accept them. if a player is more of a scorer, that's fine, but a player cannot be totally selfish and try to win the game single handedly, That just doesn't work at the Championship level.
8) Managing Salaries: This is very important. If a team significantly overpays for a player, this prevents the team from signing other good players. Basketball is a team sport, so this is critical, especially for smaller market teams.
9) Leadership: This should come from both players and coaches. The teams top player and the head coach need to get along. A leader can also be a veteran with playoff experience. There can be quiet leaders who lead by example (Duncan).
10) Luck: The team needs to stay healthy, of course, and not have a key player get injured.
Hopefully, the Nuggets can keep building toward a Championship.