Long term, yes SSB will have very little effect on Wii U's fortunes. It appeals to a large segment of the core Nintendo fanbase and we know that's no more than about 20 million people. In the short term it will help Wii U to get reasonable sales this holiday.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix