After the first three playoff matches had finished I saw that all three were 2-0 after finished their two games on homecourt. 94% of teams since 1984 have gone to the second round after going up 2-0.
You take a 52-30 team with a 27-14 road / 25-16 home team who won the regular season series and put them on their home court to play two straight matches against a 41-41 team with a 16-25 road / 25-16 home team, chances are the first team will take the first two matches. As the Orlando Magic did, against the Toronto Raptors. Anyone think Toronto can win 4 out of 5 against Dwight Howard and the Magic? Im sure there is a few eager Raptors fans who believe that, but the neutral, unbiased and clear-minded posters will all see that they don't have much of a chance.
Once the better team is up 2-0, and the lower ranked team needs to win 4 out of 5 to win. It gets hard. Only 6% of teams have actually done it in recent history. Even though the team now has two straight home games, it is very very difficult to defeat the same opponent 4 times out of 5 when they are better and have momentum on you...It isn't like it is inachieveable, it is just incredibly difficult. You look at Boston Celtics and the Atlanta Hawks, (lets just assume that Boston has won game 2) even though Atlanta has two straight games at home, how hard will it be considering that Boston is not only a much much better team but also they have momentum on them.
As we get further into the playoffs, and we see the better teams go through. We will start to see 34-7 home teams against 35-6 home teams. Home court will be fortress'es for those teams (as if they aren't already) and having the first two games at home will be absolutely crucial. If Boston gets its first two games against Detroit at home with tight wins that could be the psychological advantage that determines those final games. That could lead to Boston taking game 3 or 4 and then the series. That will be tough for Detroit, if they hit two straight losses in the finals against Boston they will be hit hard.
Once again, it isn't inachieveable (Look at Utah @ Houston) but how hard is it to win those first two on the road. Then having to win 4 of 5 against the same team that beat you twice in a row. The lower ranked teams are disadvantaged through playing harder opponents and having one less home game, which is fair and fine. But if they don't win one of those first two road games against a very good team they must win 4 of 5, winning one of those first two is vital to keeping your chances alive and that is very difficult at best.