Getting to SNES levels is pretty freaking tough.
The SNES had tons of third party support and less competetion along with a full year exclusive on Street Fighter II, which was the equivalent to CoD (ie: the "must have" third party/action game) of its time.
Even the N64 will be quite tough ... Mario 64, GoldenEye, Zelda: OoT, Mario Kart 64 ... I doubt the strongest four Wii U games can match up to those heavy hitters. Three of those games changed the industry and MK64 was a monster.
Topping the GameCube is the Wii U's best bet.
In general too I think all three of Sony/MS/Nintendo are going to have to deal with a declining market this generation, or perhaps more accurately a "normalizing" market. Last gen in a lot of ways I think was a bumper generation that isn't repeatable (no HD transition, no killer new control interfaces).
Nintendo is going to have to work their butts off to get userbase this generation, there is no free lunch in this industry, if their attitude is "we should have at least 30 million owners because we're Nintendo, now buy whatever we put out" ... nuh uh. They gotta step their game up big time with their decision making, marketing, and even games like the Marios/Zeldas ... you cannot assume people will just buy them in big numbers just because. There has to be ideas in those games that are fresh and interesting and the execution and presentation have to be well done.
