I'd think about it later in the year. However, right now I'd hold off. Paul and Ray are going to play close to 40 mpg come playoff time, so Battier is really only so much of an advantage. Furthermore, Daniels (while not putting up big stats), has been quite effective this year.
If we start losing to the likes of Miami, LA, and San Antonio because of getting burned on the wings, I'd think about that, but I'm not ready to do it yet.
Also, while it seems like 5 bigs is excessive, not only is injury history something to consider, but so is the luxury of having that many fouls. Think about it: the likes of Shaq and Perk aren't ever going to have to worry about foul trouble in the playoffs, because if Shaq and Perk both get 2 fouls in the 1st Quarter, they'll still have JO to come in (not to mention KG and BBD).
Having that luxury should allow the Boston big men to play much more aggressively, which should also translate to better overall team defense.