To the people saying it was the first good nintendo controller, I must strongly disagree... When compared against their contemporaries nintendo has a rather impressive history with controllers.
When compared with their contemporary competition:
Gen 3 (Nes): A
Introduced the directional pad we recognize today to consoles, really steering us away from joysticks. Simple, but in some ways it's the common ancestor of the controllers we use today, establishing the hands-at-the-sides approach that's easy on the wrists and places the dpad (later analog stick) under one thumb and buttons under the other, and the Japanese version featured a microphone that functioned fairly well
Gen 4 (SNES): A
Like its predecessor it doesn't look like much today, but it was a controller in a gen that featured a number of rather terrible and univentive ones. It introduced four buttons on the face of the controller in a manner that we'd still recognize today, and while side buttons had been used in awkward fashion in the past such as with the Intellivision, it introduced the shoulder buttons we also still use today.
Gen 5 (N64): B-
I feel like I should grade it lower for appearance and the analog stick's durability but it felt alright in the hand and really popularized the modern analog stick (leading Sony to up the ante with the dualshock shortly after) and also utilized the rumble pack, another feature that is now rather common
Gen 6 (GC): B+
To put it simply, it was just remarkably comfortable, well built, and featured a wonderful analog stick. Can't give it full points, though, as the c stick was (in my opinion) unimpressive and ought to have been replaced by a second analog stick, at which point this would have been a near perfect controller.
Gen 7 (Wii):
Wii Controller and Nunchuck: C-
I'll agree that it was innovative, but it was also cheaply constructed, didn't work well, and was remarkably awkward to use when asked to hold it sideways and use it as one would a normal controller which, unfortunately, came up quite often. Couple that with the nunchuck being a separate and often necessary peripheral, and you wound up with a cheap controller that was designed entirely for pointing and motion control, accomplished neither well, and wasn't even complete without the nunchuck.
Wii Pro Controller: B
When I got this controller I felt even more robbed by the original, as this one actually did what the originals claimed to do. I felt at the time and still do now that Nintendo, rolling in the dough of retirees across America, ought to have given all of us Wii owners a free pro controller as compensation for the crap they'd packaged in originally. A good controller overall.
Wii Classic Controller: B-
All I really have to say about this is "meh". They chose nostalgic aesthetics over comfort, essentially combining the Playstation's dualshock analog stick locations with the shape and layout of the SNES controller. It was alright.
Overall thoughts on gen: This was a messy one, and while their motion controls were fun at times I don't feel it makes up for the hassle of completing a darn console. Between the console, the piece you put on the tv, the original controllers and thereafter getting four pro controllers and an additional four nunchucks etc... It was clutter overload.
Gen 8 (Wii U):
Gamepad: B+
The only points off here are for the battery life (shorter than I'd have liked) and for the additional cost that prevented this console from ever being price competitive. Otherwise, it's an exceedingly comfortable controller with a fun, durable, large touch screen that one can play the games on if the TV is otherwise preoccupied, and it allows for the best internet surfing experience of the three consoles. I really like this controller and will miss it on the NX.
Wii U Pro Controller: A-
Given the wii u sold poorly and that the gamepad is required for most games, this may be one of the more criminally under appreciated controllers. Shaped much like the Xbox 360's controller, it is light, comfortable, has all the buttons you'd want right where you'd like them to be, and boasts some impossibly strong battery life. Really, my only criticisms are that the directional pad and shoulder buttons feel cheap, but this otherwise is a stellar controller.