While it's certainly true Namco Bandai has had a bumpy track record with the localization of some Tales games, it's really not as bad as all that. In the main Tales series, ie. everything that isn't a Radiant Mythology crossover game or some such, there's been 14 Tales games, if you count Symphonia 2. Out of those, only 5 of them haven't been released here, including Xillia, which should hopefully be coming here. So while there is certainly 4 games worth of characters in those Carta Cards people over here might not recognize, I think some of them are just from older, less popular games in the series.
As to why these 4 games weren't released over here, I'm not really sure. However I can speak a bit about Graces and Vesperia. For the PS3 version of Vesperia, your guess is as good as mine as to why they decided not to release it here. Vesperia for 360 sold fairly well over here, as well as in Japan. And then it seemed like Namco Bandai just lost interest in publishing the series here until they finally decided to bring Graces f over. The original Graces for Wii was pretty infamously a broken game, it was buggy and unfinished, and a lot of Japanese gamers ended up calling it a "beta" for Graces f. So it kind of makes sense that they didn't want to waste time and money on bringing the Wii version over here. Luckily we got Graces f, so can't complain too much.
As for Xillia. I dunno, I hope it makes it over here. It seems like it is, there's been some western domain name registering by Namco Bandai, so that's a good sign. The only thing I'm worried about is the fact that Namco Bandai didn't really market Graces f at all. I don't think it charted on the NPDs either, so I can only guess how well it sold. Either way, better to be optimistic I guess.