I am not entirely sure what doc Rivers is proposing but I think they should go back to the old format where the first round was 5 game series. I think it adds a little more pressure to the higher seeded teams and gives a better chance for the upset in early rounds to occur.
The NBA playoffs need to be restructured because of the way teams are seeded. Division winners face teams from other divisions that hold better records than they do. A team that has a record of 51-30 could wind up facing a team that has won more games with a record of 56-26.
The current playoff rules allow smaller teams with less of a track record to play against the bigger teams. This also gives the added bonus of adding variety to the games being played rather than allowing previously less successful teams the opportunity to succeed on a grander scale than they would otherwise be able to.
In the case of playoff reform and the NBA. I think that the playoffs have been working out just as they should and should not be changed. I know Doc Rivers and others disagree, but I have to say if it's not broke don't fix. If anything I think some of these teams just need to play better basketball.