yet another episode where bernard and rose are nowhere to be found.

where the hell did this cute couple disappear to?

According to different sources...they are committed to other projects at this time. They will be back.

I want to see them too. I had come hopes for them when they were given a flashback epi. There are a few threads that the Desmond time-loop changed the course of events and that Rose and Bernard died in the crash. When Desmond time-traveled, he altered events so that Pikki survived (when they initially didn't) and R&B died.

I think that a more likely explanation is that it takes a lot of time and money to bring back bit players to Hawaii for only a few lines of dialogue. Probably didn't make sense for TPTB to bring em back until they have something substantial to say or do.