The unifying feature of the three games involved in Operation Rainfall was that they were all published by Nintendo. Nintendo is actually localizing pretty much all of their 3DS games. For instance, if there was to be an Operation Rainfall 3DS, it would probably focus on Bravely Default, Project X Zone, and... let's say Professor Layton vs Ace Attorney.
These games are split between three different publishers (Square Enix, Namco Bandai, and Level-5 respectively). There's no simple way to petition for all three games at once. You'd be splitting your attention between three different companies, probably more since Capcom is also involved in PLvAA, and since people who don't know any better would continue shouting at and blaming Nintendo for these games not coming over.
There is an alternative. Patience. Rainfall was sparked by the revelation that Nintendo did not show the games at E3 because they did not plan on releasing them in America. The Wii was at the end of its life, so there was a definite "now or never" vibe to the campaign. The 3DS, on the other hand, is just getting warmed up, and there is no such information to suggest that these games will not be localized. Give it time.
If you want to petition anyone, I say petition Level-5. They've released quite a few games in Japan that have little chance of coming to America, because they have little chance of selling well at all in America. Inazuma Eleven, Time Travelers, Girls RPG -- these games (excepting IE) didn't even sell well in Japan. Level-5 will need some convincing that these games will sell before bringing them West, and for good reason, because they likely won't.
