Gah. After some updates I was able to install xserver-xorg-input-wacom. No change. Probably the most interesting part was this excerpt from Xorg.0.log:

(**) Option "Device" "/dev/input/by-path/pci-0000:00:13.1-usb-0:2:1.0-event-mouse"
(**) stylus: always reports core events
(**) Option "Mode" "Absolute"
(**) Option "Touch" "on"
(**) Option "Button1" "1"
(**) Option "Button2" "3"
(**) Option "Button3" "2"
(II) XINPUT: Adding extended input device "stylus" (type: STYLUS)
(--) stylus: using pressure threshold of 15 for button 1
(--) stylus: Wacom Unknown USB tablet speed=38400 maxX=9600 maxY=7200 maxZ=256 resX=1016 resY=1016  tilt=enabled
(--) stylus: top X=0 top Y=0 bottom X=9600 bottom Y=7200 resol X=1016 resol Y=1016
(**) Option "Device" "/dev/input/by-path/pci-0000:00:13.1-usb-0:2:1.0-event-mouse"
(**) eraser: always reports core events
(**) Option "Mode" "Absolute"
(**) Option "Button1" "2"
(**) Option "Button9" "0"
(II) XINPUT: Adding extended input device "eraser" (type: ERASER)
(--) eraser: top X=0 top Y=0 bottom X=9600 bottom Y=7200 resol X=1016 resol Y=1016
(**) Option "Device" "/dev/input/by-path/pci-0000:00:13.1-usb-0:2:1.0-event-mouse"
(**) touch: always reports core events
(**) Option "Mode" "Absolute"
(**) Option "TopX" "0"
(**) Option "TopY" "0"
(**) Option "BottomX" "9600"
(**) Option "BottomY" "7200"
(**) Option "Touch" "on"
(II) XINPUT: Adding extended input device "touch" (type: TOUCH)
(--) touch: top X=0 top Y=0 bottom X=9600 bottom Y=7200 resol X=1016 resol Y=1016



(II) config/udev: Adding input device "HID 1b96:0001" (/dev/input/event7)
(**) Option "Device" "/dev/input/event7"
(II) "HID 1b96:0001": type not specified, assuming 'stylus'.
(II) "HID 1b96:0001": other types will be automatically added.
(WW) "HID 1b96:0001": device file already in use by stylus. Ignoring.
(II) UnloadModule: "wacom"
(EE) PreInit returned NULL for ""HID 1b96:0001""
(II) config/udev: Adding input device "HID 1b96:0001" (/dev/input/event8)
(**) Option "Device" "/dev/input/event8"
(II) "HID 1b96:0001": type not specified, assuming 'stylus'.
(II) "HID 1b96:0001": other types will be automatically added.
(**) "HID 1b96:0001": always reports core events
(II) "HID 1b96:0001": hotplugging dependent devices.
(**) Option "Device" "/dev/input/event8"
(**) "HID 1b96:0001" eraser: always reports core events
(II) XINPUT: Adding extended input device ""HID 1b96:0001" eraser" (type: ERASER)
(--) "HID 1b96:0001" eraser: using pressure threshold of 15 for button 1
(--) "HID 1b96:0001" eraser: Wacom Unknown USB tablet speed=38400 maxX=9600 maxY=7200 maxZ=256 resX=1016 resY=1016  tilt=enabled
(--) "HID 1b96:0001" eraser: top X=0 top Y=0 bottom X=9600 bottom Y=7200 resol X=1016 resol Y=1016
(**) Option "Device" "/dev/input/event8"
(**) "HID 1b96:0001" touch: always reports core events
(II) XINPUT: Adding extended input device ""HID 1b96:0001" touch" (type: TOUCH)
(--) "HID 1b96:0001" touch: top X=0 top Y=0 bottom X=1024 bottom Y=1024 resol X=1016 resol Y=1016
(II) "HID 1b96:0001": hotplugging completed.
(II) XINPUT: Adding extended input device ""HID 1b96:0001"" (type: STYLUS)
(--) "HID 1b96:0001": top X=0 top Y=0 bottom X=9600 bottom Y=7200 resol X=1016 resol Y=1016