Steer well clear of Akiba's Trip on the Vita. I like the premise, and I like how you win fights by stripping your enemies down to their undies. It plays like shit, though. The Vita version is just a complete mess from a technical point of view. If you want anime games you may think the Vita has you covered. Well, quantitavily speaking, that is most definitely true. Most of these games hail from the weird lolicon school of anime, though. More importantly, most of them are cheaply thrown together garbage you're not gonna like regardless of whether you can deal with that subject matter or not.
I couldn't get on with Ys unfortunately. Mostly due to how awful it looked. (which is not something that usually bothers me to such a degree. I finished Nier and I have 1000 gs in Bulletwitch
)
Here's a bunch of stuff I enjoyed:
Dragon's Crown: cannot go wrong with that one really. It's basically a side scrolling Diablo, but with a bigger emphasis on player skill. Looks gorgeous on the vita too.
One Piece Unlimited World Red: Another brawler type game. Love the boss battles and I also dig the visuals. This was primarily developed for the 3ds I believe, but an upgraded 3ds game seems to suit the Vita better than a crippled console port. It's colorful, quick and well optimized.
Both Atelier Totori and Atelier Meruru: saccharine as shit, but also genuinely sweet. The ever present time pressure is probably a huge turn off for most gamers.
I think if you want a trafitional jrpg your best bet is still the FFX collection.