Yeah, you're right, but I don't think any amount of grinding would have helped you with her. You just gotta be pretty fucking lucky half the time, keeping at least one member in zombie, so when she uses Megadeath (Or Slipknot, Cradle of Filth, whatever the spell was called) on you, you can phoenix down like crazy.
Just noticed this.
This is the argument that causes RPG's to be nothing more than grindfests. You're essentially complaining that this boss was bad because you couldn't grind past her, and that you had to use a strategy to defeat her. IMO, Yunalesca was the most interesting boss in FFX simply BECAUSE you couldn't beat her without the right strategy.
Of course, even then she wasn't really that bad. You just never heal Zombie ever unless you need to regain HP. That's the entire strategy against her.