Let's be real, there is one round to many in the NBA playoffs, and then to stretch a seven game series out over 2 weeks is just ridiculous. Unfortunately there is too much money in it, the seven, game first round series is here to stay and it will be long. The NBA should take a lesson from baseball, play less, more often and the series actually has a "feel" to it, so many of these seven game series, especially the first ones, are so long you almost forget what's happened in them, making it difficult to really get into the series.
As for the Celtics, the momentum loss could be an issue, but the C's seemed to have ramped up their intensity even more for the playoffs, having homecourt throughout and a LOUD crowd will definitely help.