Haha! You're asking the wrong person. I'm willing to bet that you've actually played more JRPG's than I have (I literally only have Xenoblade, the Golden Sun games, the Pokemon games, Chrono Trigger, two Final Fantasy games and one Ys game under my RPG belt).
Regarding Ys, I've only actually finished Ys Seven on the PSP. And I've had a lot to say praising its combat system. And while its plot wasn't anything particularly special, it did have a satisfactory amount of mythology and was relatively unintrusive. It has a grand total of one reference to the plots of past Ys games, and is apparently relatively easy compared to them, which makes it an adequate starting place for newcomers to the Ys series. Unfortunately, it's on the PSP, which drastically cuts its "welcome to the series" capabilities.
Then I went to play a bit of Oath in Felghana on the PSP. I noted a slight decline in the combat - for me, fighting airborne enemies was the most frustrating thing ever. It was also slightly less fluid than Ys Seven combat, with fewer interesting combat-related choices to be made. I'm told Origin has a similar gameplay style but greater variety. These were a dealbreaker for me so I quit Felghana partway through, but if you can get over those, then I'm sure Felghana and Origin can sate your fast-paced RPG fix
