the games I've done it with didn't need knowledge of other languages to play. There's a reason I refuse to import PS3 Vesperia even though I could play it by looking up guides for everything.
I've never done it on a PS3 game though, but I have
Breath of Fire 3 (PSP Europe version) Mushihimesama Futari (360) ESPGaluda II (360) Eschatos (360) Muchi Muchi Pork & Pink Sweets (360) DoDonPachi Resurrection (360 Europe version) DoDonPachi SaiDaiOuJou (360)
I also have Deathsmiles II via 360 Games on Demand because that was the only way to play it in the US officially.
Only PS3 game I can think of that I'd consider importing at the moment would maybe be Ketsui, but then I remember I don't really like Ketsui, so I'd pretty much be risking whether I like the X-Mode or not, which I don't feel like getting it to check that.
So the one RPG on the list was in English anyway and the others didn't require any knowledge of the language to play. Would have gotten Tales of Eternia on PSP if I didn't have to worry about getting a broken version that'd be unplayable since one of the prints is broken at a certain point and the others work.
I pretty much liked all of those except for both DoDonPachi games. Didn't end up playing very far into Breath of Fire III, though maybe I'll try again sometime.