One of Sony's DualShock 4 prototypes featured a touchscreen, but this was ultimately scrapped in the final version in favor of the touchpad because developers didn't like the idea of having players divert their eyes from the main screen during gameplay, product planning manager Toshimasa Aoki has said.

"A touchscreen was another idea that we had," Aoki told GamesBeat. "We actually tested it, but [besides cost factors], our game teams felt like having to look down at the controller is not what they want to do. They want to have the consumers concentrated on the big picture that they show [on the TV]."

Nintendo's Wii U features a touchscreen for its GamePad controller. Players can use the touchscreen to navigate menus, inventory, and maps for various games.

Nintendo asserts that the GamePad opens up entirely new methods of play, but this functionality has not been universally praised. Tekken boss Katsuhiro Harada said looking back and forth between two screens is "distracting" for fighting games.

Also in the GamesBeat interview, Aoki explained that at the very start of the design process for the DualShock 4, Sony considered "drastically changing" the controller.

"We tried out new devices, changing the form factor. We'd start from there and then try to talk to the game teams and tweak toward what the best form would be to have for those new devices," he said. "So we made, I don't know, more than 20 prototypes. Some had no buttons, just touch panels. Some were rounded. All this crazy stuff."

Sony even looked at the Microsoft's Xbox 360 controller for inspiration, Aoki said.

"For the analog sticks, we did test having the analog sticks on top, since the Xbox has the left side on top [above the D-pad]," he said. "Especially from the shooter teams--we got feedback that that's what they wanted. They knew that consumers liked the 360 for shooters."

Aoki explained that Sony tested numerous combinations of analog stick placements, including two sticks at the bottom (like the DualShock 3), two sticks offset (like the Xbox 360), and two sticks at the top (like the Wii U GamePad or Pro Controller).

"When Nintendo came out with that, we were like, 'Wow, that's just like our prototype!’ That surprised us," Aoki said.

Ultimately, however, that stick placement "just wouldn't work" because it would break players' muscle memory, Aoki said.

The PS4 launches in North America on November 15 and November 29 in Europe. A DualShock 4 controller is included with every system and can be purchased separately for $60.