I've never gotten the ridiculous appeal Rei has to some people. I mean, I suppose it's endearing that she slowly develops into a human being, and her
was something I'd been waiting a long time to see, but otherwise, I dunno. I don't see the appeal.
Like, Misato I get, because she's overtly sexual, and the only adult woman in the series to so be, in addition to the one person who actively and consistently tries to show Shinji love throughout the series. Asuka is obvious if you've got a thing for Tsunderes, or the Ms.Badass, which make sense.
But Rei? Like, I dunno. In ReBuild, sure, because Rei's development is more obvious due to being compressed, but in the TV series, until EoE, she's a very shallow love interest and an uninteresting character. I mean, she's an interesting part of the show, but as a character Rei is incredibly dull (and 99% of all Rei clones are worse) for the major part of the show. It's only really at the very end that there's any reason to care.
So why, exactly, have so many people latched on to Rei? The only thing weirder would be to find out there was a deranged cult following for Ritsuko's mom.