Valve's original vision for a PC gamepad was an arresting deviation from the norm: touch-sensitive control pads in place of dual analog thumbsticks and a full-on touchscreen in lieu of actual buttons. The company's latest revision -- codenamed "D0g" after the character from Half-Life 2 -- skews a little more traditional, replacing the curious touchscreen with eight regular buttons. Is it a loss worth lamenting? We caught up with Valve at GDC 2014 to find out.