It's a little strange that the year of Luigi is ending, then a month later they're release NES Remix 2, which features the backwards version of SMB with Luigi as the main character...maybe they really do want a second year of Luigi.
I agree with it being Yoshi, everyone loves Yoshi and there's already a couple games being worked on with Yoshi as the star. And I'd be all for a New Yoshi Bros Wii U DLC, even though I haven't gotten to play the Luigi one yet.