Nintendo released most of their big titles in the past 2 years - Zelda, Mario, Kart, Smash, to name a few.
Now, why don't I see more threads that say "Why hasn't Bungie released a new game yet?" Or "Where is Blizzard's new game?" Or "Why no GTA5 this holiday?" I could go on.
My point is, Nintendo is always held to some goldy status of needing release games every 3 months... and they kind of do... they release dozens per year, and they do a lot. I just think it's ridiculous to expect "harder core, AAA titles" from Nintendo, multiple ones, every single year. Games take years to make, if not longer.
There was only 1 Zelda game on SNES.
There was only 1 Mario Kart game on SNES.
There was only 2 Zelda on N64.
Only 1 Mario Kart on N64.
Only 1 Mario Kart on GCN.
Only 1 Mario on SNES.
Only 1 Mario on N64.
Only 1 on GCN.
Only 1 Smash Bros. on N64.
Only 1 Smash Bros. on GCN.
Only 1 Metroid on SNES.
NO Metroid on N64.
A rare 2 installments of Metroid on GCN.
So far, we have 1 game of Zelda, Kart, Mario, Smash, Metroid, some others, on Wii already.
Think of it this way... if and when you get a second game of the major serieses, you're getting a very rare bonus from Nintendo at all. The more demanding is made of Nintendo, the more disappointed you'll be. Even though communications now move at the speed of light, it doesn't mean developers are able to think and produce at the speed of light.