They have multiple iconic controllers (;

They actually do have an iconic controller. Many of them, in fact.

It's just that they never carry over the designs. Which isn't an inherent problem as long as each one is good and comfortable.

The WiiU controller(s) are on par with anything the other two are offering. Some may actually prefer them. They keep changing the design while the competition keeps it pretty standard, it's true. Still, nobody should have any problems switching between the three (or four if you count the Pro).

GC controller

See below

Not iconic huh?

I could do more for the SNES, N64, Wii, etc. but why bother. 

You're right. They don't have an inconic controller... they have many!!

"They Have No Iconic Controller!"

You've lived in a cave for the last 20 years?

Now try using a Nes controller to play an eight generation game and let's see how that works out ;-P.

Nintendo has iconic controllers, just as mentioned in the OP though not an iconic controller which can be used gen after gen with only minor tweaks. The WII mote is iconic but will they keep using it gen after gen? No!

They have iconic controllers everywhere.

anyway, every gen they add stuff that makes the controllers better. they aren't like sony and, to a lesser extent, MS, that keep the same obsolete controller gen after gen.