There have been critiques of the show that question the writers/producers about the background losties. Listening to the
Expose podcast I got the impression that Nikki and Paulo were largely the result of addressing these questions. But it got a lot of mixed reactions, or actually mostly bad reactions. It seemed to kinda go down like this:
viewers ask hey there are supposed to be like 40 survivors how come you only ever show about 10 of them doing anything.
the show responds with Nikki and Paulo
many viewers say "who hell are these guys and why should I care"
the writers/producers are like ?? ok we attempted to give some incite on what some of the other surviors are doing and make it entertaining/interesting to watch. But the same people that complained about not showing background characters now are complaining about Nikki and Paulo. So the writers/producers are like WTF try to give people what they ask for and they don't like.
This is just my opinion and I am in no way pointing fingers at anyone here.