IMO, Rika shouldn't even have existed. It only exists because PSIV team blundered the PS series story in order to make a PSIV which would induce nostalgia in PS players. It is a complete sell-out in my opinion and, because of that, the worst.
If the developers were mature enough to live with the fact that Numans were a bio-engineered species by accident that have gone for good in PSII, they would have not taken the meaning of Nei. As they weren't, Nei has become a pointless character.
I voted Nei because of what she was at the time she was made and before PSIV spoiled everything.