Oh, I'm not against the decision to bring in some new characters to the story at all. Some fresh blood wouldn't go amiss in a few of the episodes. What annoyed me about Nikki/Paulo until their last episode was that they seemed so useless. They simply didn't seem to add anything to the story. We didn't know anything about them and they didn't really have a backstory to explain where they came from until the very end. They felt like a couple of extras who came out of nowhere and tagged along.

Having said that, their last episode had some nice insight to the pair and showed their character too. I wish they did that earlier I guess.