I get ya. It appears that you're a pretty big fan of...er, uh. I know it starts with a G. Well dang it. This is one of those cases where not staying with the series gets you in trouble.
*search* Giratina! There we go. Good ol' internet, you save my butt once again. ... hmm, honestly, Giratina is still more appealling than a lot of other Pokemon, to be fair (I still can't get past Rayquaza wearing lipstick).
I'll try to keep this short. Generally, I love Nidos. I do my best to vouch for them, because to me, they're all a bunch of underdogs with potential. Maybe not in game potential, but definately in intrest and personality. I think the one Nido I really gravitated towards was Nidorina, because she was the most underdoggy of them all.
I paid her about as much mind as I did anyone else at first, but I wrote a story about one many many years ago (and every other Pokemon in the first Generation). The story was really sympathetic to Nidorina, so I became attached to the character. Essentially, she became a favorite of mine, and made me tolerant of the species itself.
Silver came along, and I had a Nidorina on my team that was really helpful, and I loved taking care of it in a slight virtual pet fashion. I took her to the salon regularly, and gave her a pink bow (more to accessorize than as a use, I like to visualize stuff like this). In high school, my friend and I would write comics about our adventures in Gold/Silver, as well as other games and stuff we did on the internet (it's all the same comic). The Nidorina in my game essentially became a character too. In fact, that's her in my avatar. So with this Nidorina and the other Nidorina becoming really interesting characters to me, I really started to love the species.
So a lot of it was giving unique personalities to Pokemon I'd've otherwise ignored, but if I never wrote that old story, I'd never use one in Silver. And without Silver, there'd be no Nidorina (the 2nd). Without her, there wouldn't be all the others that came after, and the appreciation for the species as a whole (one's even based off of my Nidorina in the first PMD, so the tradition of giving life to sprites continued). So I can honestly say that even the games played a part in this.
Officially, Nidorina can be charming in some of her art. I really loved her sprites in the 3rd generation, it was like they were going back to the way she was supposed to look afterall. By why didn't she look like that in promotional art? Well, she did! But it never caught on. Instead, the Pokemon company used the anime designs and kind of ruined her reputation of appearing somewhat calm and maternal, like her original art from Sugimori.
Copypaste from Toxic club:
As stated, that's the anime's fault (which in turn, erroneously used the sprites from Pokemon Green), and I was essentially able to prove that. Nidorina, for all intents and purposes, was supposed to look like a feminine Bulba/Ivysaur at best, but Sugimori's art was ignored. It's something I point out a lot, because it's such a misconception that at this point is very widespread, especially since marketing, merchandise and the like have used the anime as a guideline, and not Sugimori. So hag-Nidorina became the variation everyone knew her as. Fortunately, recent measures have been taken to rectify that officially, but it may be a bit too late.
I should point out that the current artwork Sugimori has produced of the Pokemon is sort of a fusion/compromise of his art and the anime's, which in a way actually borked up Nidoran Female and Nidoking (Nido F has less of an animal's anatomy now, and Nidoking looks a LOT less menacing) to a degree. But it really streamlined a lot of others. Fortunately, Nidorina's still based moreso on his original design, but she's less fat and a little less maternal in appearance.
I do a lot of research on Nidos, or at least I did. I think I've tapped out every source at this point, so there's really nothing else to report on. But at the time, finding out stuff like this was really interesting. Nidorina today tends to look better in official stuff than she did years ago, but not as good as she could have, as she lost that maternal aesthetic. She looks slightly tougher, but at least she doesn't look like a pig/pug anymore.
So yeah, going by what may have been the original intentions, Nidorina was the calm, caring one and Nidorino was the brash, protective one. And while the Pokedex entries still say this much, in appearance, today Nidorina looks more slightly more scrappy and Nidorino looks more mellow. Maybe their personalities rubbed off on each other. I dunno.
Fan art, including my own and others, can also make any Pokemon look cute in the same way that the anime can (sometimes). It also establishes endearment. The games and guidebook art alone can't always do it for you. Pikachu may be cute right off the bat to some people, but for others, he's just a goofy looking critter. Adding some personality to that is what makes Pikachu endearing. Why do people still remember Pikachu and his newfound love with ketchup? It added something to THAT character of Pikachu, and instances like that can rub off into the species as a whole.
And then if you just want the absolute cheat of an answer, according to generation 3, Pokeblocks can make every last Pokemon on the planet cute. Or smart. Or beautiful. Or whatever. It seems to alter the complexion of Pokemon, or their appearances and mannerisms or something. A lot of in game text basically states that it changes the way they appear. That raises a lot of morality questions, but there you go. Go make your Feebas beautiful (who will later become a pariah among other Feebas).
Well. So much for short.