Windstar
[12] Conqueror
Super easy to learn. Aside from a few moves (Izuna drop, for example) everything is pretty easy to pick up and play.
Kokoro only came into the series in DoA4. I'm not sure which tournament footage you're looking at, outside of perhaps some DoA5 stuff. In DoA4, though, she was considered particularly weak or low-tier due to the fact that many of her moves and strings started or ended with a mid hit; making them easy to counter. It's actually a bit more complicated than that, but that's the simplest explanation. With DoA5 and the return of the 4-point counter system, Kokoro might have less of an issue being countered all the time.
A couple things to keep in mind with Kokoro and her rarity. A large chunk of players originally played DoA on the Playstation systems, before DoA3 and 4 became exclusive to the Xbox and the 360. DoA 4 also had a rather limited run as a launch title on the 360. Good luck finding a new copy compared to DoA3, and the Hardcore which featured Hitomi playable in DoA2's remake. A bulk of the character favorites like Kasumi, Lei-Fang, Ayane, Hayabusa and more were already in the game by DoA2. Since DoA2, we've only seen five new characters; Eliot, Hitomi, Brad, Kokoro and Lisa. If you notice, Eliot, Brad and Lisa are also equally rare in most tournament footage. Finally, Kokoro's personality is... not very popular. She's a geisha-in-training and is surprisingly naive about many things despite the fact that she's older than Ayane. She's fairly flat, even for a fighting game character and has a personality that some players might not like.
If you're looking for some play of Kokoro, you might check some of Kayane's play from more recent DoA5 tournaments as she recently switched from Kasumi to Kokoro. I don't know the specific reasons why (maybe she can enlighten us if she knows this thread exists?) She does fairly well with her, but I think once Kayane gets the full game and is able to study the move lists, she could dominate with Kokoro.
