I think a lot of that had to do with the fact that the actors were never told what their characters history was in advance. So whenever they had a scene alluding to some deep, dark secret from their past, they were basically flying blind. Kate (I forget her name - Lily?) played those opening episodes with so much angst, that when she finally got her history revealed, it didn't measure up to the weight she had given it in the early episodes. I felt that was the case with many of the actors on LOST. It handicaps them in a very real way. I think the same will happen for the actors on Revolution if they are kept in the dark about their backstory in the overall narrative. I remember reading an interview that Alan Rickman gave where he said J.K. Rowling revealed to him (and only him) what Snape's story was all about. I'm sure that helped him immensely in the early movies to give a more nuanced performance.