Namco Bandai's publishing of Tales games may look irregular, but in defense of the company, it generally does have numbers to back up its decisions. Fans get mad at the company, the company shrugs its shoulders and expresses that it can't be sure if it will make money on these deals. Before looking to the future, let's glance at the past.
Tales of the World: Radiant Mythology for PSP made the swim, but due to poor sales and a critical slamfest, neither of the two sequels would see the inside of an American retail shop. This is a shame, because by all reports, those two sequels are considerably better games than the first. Some fans might get mad at Namco Bandai for not localizing those, under the justification of "But I'd buy THOSE because they're GOOD!" But you have to consider also that you're not the one sinking thousands of dollars into that gamble. PSP games have been a hard sell in North America, and the first game sold poorly. Can you really fault the publisher too much for its decision? The guys there are, after all, trying to keep their jobs.
While Namco Bandai's track record of localization might not be perfect, one must keep in mind that just because a game is released and gets good reviews, and you liked it, does not mean it made money. Quite to the contrary, there are plenty of games every year that achieve plenty of praise, but represent a financial loss for its creators.
The Wii version of Tales of Graces didn't come over because Namco Bandai didn't see many other RPGs on the Wii and therefore can't be assured that the audience is there—kind of the same justification Nintendo of America used for Xenoblade. Is it bullshit? To an extent, yeah, but these kinds of factors do come up in a games retail success (or lack thereof). Similarly, Tales of Vesperia for PS3 wasn't localized because Namco Bandai couldn't be sure how much it would sell, since the Xbox 360 version had already come over. Again, you might be sitting there thinking about how you don't have a 360 and you and your friend Chad would totally both buy PS3 Vesperia, but Namco Bandai does not know Chad, and Chad's dollars would only cover a few in a pool of a whole lot more needed to pay off the publishing investment. As much as it hurts gamers—myself included—to admit, just because a certain percentage of our friend would buy a certain game, it does not mean that same percentage of gamers would buy that game.
Next year will see at least two Tales games shipping in North America, with Tales of the Abyss coming to 3DS and Tales of Graces f (yep, that's the full title) arriving for PlayStation 3. Namco Bandai is delivering the goods, so now is the chance for all Tales fans to show how much they really want more Tales games coming over. Would you like to see PS3-exclusive Tales of Xillia come to your territory? How about the Vita remake of Tales of Innocence? Then buy the localized versions of Tales of Graces f and Tales of the Abyss. If they sell well, then Namco Bandai's excuses of yesterday are rendered invalid. If you don't buy them, you've got nothing to complain about if you miss future Tales games.