You all got me beat. I started playing Dead or Alive when it was on the PS2 with Dead or Alive 2. I didn't get back into the series (since I didn't own an Xbox) until Dead or Alive 4.
Fought a Pai player today. After beating him a couple times, he switched to Hitomi, then switch to Kokoro after beating his Hitomi several times. By this point I figured out he was just spamming strings without much logic behind them. So after I beat him a couple times playing Kokoro he switch back to Pai and I started playing her. I hadn't played Pai since VF2, so it was basically a new experience for me when I started playing her again. So while I was playing his Pai against mine, I was basically using the good ol' PPPK, PPPPK, PPPP2K strings and learning her new stuff in the process. I found out that her high counter hold guarantees 9KK and eventually, that her 9K is an insanely fast anti-low against Pai's own 3P and 1K.
It was a rather interesting experience, though, the player himself/herself wasn't very good and while I was taking the time learning Pai, he/she was having trouble beating me. After a couple of games I think he began to learn some stuff, but it was hard to say. He kept using a lot of different moves whose commands I didn't really know, but I did pick up on his patterns and blocked and punished. I'm not sure, but it seems like Pai's basic PPP string is a natural combo, so it was actually kind of easy to use that as a poke and apply pressure and watch for whiffed counter-holds and follow up with that. To me, Pai pretty much felt like she played back in VF2. Albeit with much nicer animations these days.