Splatoon will be a system seller, I expect a major boost, it wont be in the same vein as MK8 unless it has a bundle but it should be pretty significant. There are 3 games that will provide major boosts to the Wii U this year. Zelda, Splatoon and Xenoblade. They all shoot for different demographics and should do well to pull them in. I think a lot of people are underestimating what these 3 games can do.
What is your definition of a major boost? How much do you think Xenoblade and Splatoon are actually going to sell?