Sounds like you need to play against a good Jin, WGS. Not a scrubby one either. A really good one. Let's see you complain about Nu then.
>__> Seriously, bro. She's good but she is not THAT good.
Smooth Criminal
I've played a couple really good Jins, and yes, they can be a pain to play. Heck, the whole cast can be tough, really. Thing is, Nu is better than all of them. She has solutions to everything every character can dish out. No matter who you use, short of a ditto match, she is at the advantage, even if it's a slight one. There's something to be said about a character who wins every matchup.
Again, YES, I know you can beat v-13. It's clearly possible, without a doubt. That doesn't mean her character doesn't naturally have an advantage. From fullscreen she can **** your face, and short of bursting, you pretty much can't do anything once she gets you. Yes, every character pretty much has half-to-full health combos, but Nu has the ones with the least amount of danger involved for her.
EDIT: Oh, and for future reference, most of this isn't from my own perspective/experience. The info/thoughts I've gathered have come from watching pro vids. I know I'm not a professional at this game, and I doubt anyone I've played is either. I'm just responding to what I've seen in the pro-circuit and the opinions I've heard from those who do play at a professional level.
EDIT2, ELECTRIC BOOGALOO: Rachel is amazing, but I don't like goths. Therefore, I give her third place. XD