As video games have grown more complex and the technology better the controller has also consistently grown more complex. Bottom line - The more buttons means more progress of gaming.
A short overview* looks something like this:
Pong - ONE input. The beginning of consumer gaming had a potentiometer as the control input. Crude. Primitive.
Atari - TWO inputs. One button and one analog joystick. Better than one potentiometer but a severely limited control interface.
NES - FIVE inputs. D-Pad, A and B button, Select and Start. For most of the gameplay it added one button since the Select and Start were used infrequently in most games.
SNES - NINE inputs. D-Pad, A/B/X/Y, Left/Right Shoulder, Select and Start. Functionally more like seven inputs. A great leap in the the number of buttons and the path to more complex gameplay.
N64 - 12 inputs. D-Pad, A/B, Left/Right/Z, four C buttons, Start and the Analog Joystick. Nintendo did gamers a great favor by bringing back the Analog Joystick. Three more ways to push buttons pushed games from 2-D to 3-D.
PS2 - 15 inputs. D-Pad, X/[]/^/O, four shoulder buttons, Select, Start, two Analog Joysticks and Joysticks work as buttons. The addition of the second Analog Joystick was an evolutionary leap in adding more complexity to gameplay.
Wii - 10 inputs. D-Pad, A/B/Z/C/1/2/+/- and Analog Joystick. A step back.
PS3 & 360 - 15 inputs. Holding fast to last-gen standards.
PC - 101 inputs (keyboard) plus Mouse. The ultimate controller for numerical superiority in the realm of gaming complexity. Consoles have a lot of catching up to do.
Each generation the number of inputs has grown until this generation. As the number of inputs became greater the complexity of gameplay grew and (some say) games got better in part because of that. The uncontested leader in input prowess (and graphical prowess) is the PC. Because of that the PC has the most potential for complex gameplay input schemes.
Until consoles add more inputs they will not be able to match the PC in its sheer multitude of input choices. If consoles ever hope to catch up they must start adding more buttons, D-Pads or Joysticks... or maybe a mouse and a keyboard? Perhaps in the next generation we will see more complex input schemes created for the consoles. If consoles don't add more input options will they be forever doomed to a numerical disadvantage with the PC?
Bottom line: The more intelligently placed buttons means more progress for gaming.
*not comprehensive
