Is it really that surprising though? It's not going to get an adult rating by any means, and let's be honest, Nintendo's quality standards are super low as far as quality content goes (Superman 64, really?). Nintendo is not outside of allowing suggestive content on their machines either. Case in point: Zero-Suit Samus, not to mention all the suggestive things she does and what Snake blatantly says about the character in Smash Bros Brawl. And Conker's Bad Fur Day for the N64 was released by Rare when they were a 2nd Party, arguably when Nintendo's reputation as a child-friendly family company was even stronger. All of these examples were either made by Nintendo or published by them, too; it doesn't count any of the 3rd parties. Samus particularly in Brawl is blatant sexual fan service and that's Nintendo's own property. They knew what they were doing.
We Dare is a special case because of its ridiculous trailer and premise, but it's suggestive nature is, in actuality, pretty silly more than anything else. Don't get me wrong, it certainly is unusual, but its not like suggestive or sexual titles haven't been released before on a Nintendo system. As far suggestive material goes, it's pretty tame.
It'll get slapped with a "Suggestive Themes" for the rating and get rated M probably, but that's about it.... and get way more marketing and press than it deserves probably.