I agree with Ian that Nintendo needs to launch strong on first party games at start of launch, and provide a launch lineup that Nintendo fans and gamers can find a bit of everything for them.
In the end, Nintendo games will sale if they are good. The numbers won't be great at first if there is more variety but over time all games will sell well, and even better if the launch attracts more people.
I do think that franchise games are Killer Apps.
Halo was a first person shooter, but it became popular and became a killer app.
Now Halo is a franchise and is still MS's top killer app for the new system.
Grand Theft Auto is a franchise and is now killer app material.
As is Final Fantasy, Madden, Mario, Zelda, Mario Kart, and many many more.
The name recognition is important. It alone can make a good game GREAT (in sales)
and if its a GREAT game then it makes it incredible.
Legacy franchises are even more important. Franchises that have a record of consistant quality are legacy because people recognize the name and understand the quality they are getting in the game.
A new IP is not needed for a killer app, just something recognizeable that a GOOD game.