Well I would say that Miami's biggest issue is that you can't predict which player will show up or who won't show up when it comes to being productive in games. Lebron James is the only one who consistently shows up but because of that every season I think he will begin showing signs of fatigue which could lead to him being less of an impact player and career ending earlier then expected because of fatigue. Dwayne Wade because of injury is not even close to who he use to be as a player. Like Dwayne Wade was missing open shots and playing basically no defense in the finals. Chris Bosh wasn't really productive in the finals either. Then Miami also had no consistency with the rest of their players on the bench. I mean their most effective player off the bench was Ray Allen who is 38 now and will be 39 in a few weeks so he won't be playing a role in winning possible future championships because he will likely retire soon.
Since Miami lost the way they did people are questioning will Lebron stay in Miami or leave because he has really been the only consistent player on his team (which is basically how it was in Cleveland for him and which is why he left there). It is almost a guarantee if Lebron leaves he will go to another Eastern Conference team so he still has a chance to make it to the Finals easier because it is the weaker conference whose only other good team is the Indiana Pacers. If he goes to the West it isn't such a guarantee that he will make it to the Finals because it is the stronger conference that consist of many teams that are continuously making it to the playoffs or are constantly getting better like the San Antonio Spurs, Oklahoma City Thunder, Los Angeles Clippers, Dallas Mavericks, Golden State Warriors, Houston Rockets, and Memphis Grizzlies. Yes Lebron would make it to the playoffs if he went to one of those teams in the West but going to the Finals isn't as much as a guarantee in the West. It would be easier to make in the Finals continuously if he stays in the East.
I've been a Spurs fan for years so I'm happy to see them win the Finals especially after coming within seconds of winning in last years game 6 of the Finals. Coach Popovich made changes which included working more on defense, shooting 3-pointers, rebounding, and passing. He also allowed his team to rest having no player averaging more then 30 minutes a game. Tim Duncan is 38 and Manu Ginóbili is 36 so they need rest to be completely effective/not fatigued. Tim Duncan played better than he did last year when it came to rebounding and Manu Ginóbili lost weight/is healthier compared to last year.
Since Coach Popovich made changes it allowed the Spurs to have more depth with their team. They have Tim Duncan, Tony Parker, Manu Ginóbili, Kawhi Leonard, Danny Green, Patty Mills, Tiago Splitter, Boris Diaw, and Marco Belinelli who can be effective in every game. That is 9 players from a roster of 15 players. The other 6 players can also be effective if needed (specifically Cory Joseph and Matt Bonner). Because of the depth they were considered to be the better team in the Finals but I don't think anyone could've predicted that the games in which the Spurs won would be games that were won by 15 or more points (Game 1- 15 pts, Game 3- 19 pts, Game 4- 21 pts, Game 5- 17 pts.).