When it was officially announced that the Ice Climbers would not be making an appearance in Super Smash Bros. 3DS and Super Smash Bros. Wii U, there was much outcry. It’s understandable, given the Ice Climbers were a unique, complex, and ultimately rewarding character to play and master.
The reason for their removal is that Super Smash Bros. director Masahiro Sakurai wanted the 3DS and Wii U versions of the game to be equal in content and unfortunately, the Ice Climbers proved a bit too difficult to program for the 3DS. So they were removed from both versions.
Still, evidence exists for the attempt made to put Ice Climbers in the 3DS version of the game. A gamer named Gema Yue discovered an interesting glitch while playing a Japanese version of the game. Under some odd conditions which included playing as the Villager and KO’ing two Dr. Marios at the same time, a chant began ringing for “NANA, POPO, NANA, POPO~!” (around the 12 second mark).
Nana and Popo are the Japanese names for the two Ice Climbers; and while the video updated saying that Japanese players in fact heard “Murabito,” having seen the video myself it certainly sounds like “Nana” and “Popo” to me.
Sakurai explained that the codes for Ice Climbers were too old to be functional and have to be rebuilt from the bottom-up, so there’s still hope the duo will be released as DLC further along the line.