Input tablet devices (i.e. Wacom-type devices) now have support by libinput for the extra information exposed by the tablet, stylus, and any extra buttons. Missing though at this time from this initial set of 24 tablet support patches is handling of tactile strips or wheels and there's other basic shortcomings.
These initial 24 patches for tablet support within Libinput were done by a GNOME developer, Carlos Garnacho. These patches can be found on the Wayland-devel mailing list and with GNOME's Mutter-Wayland also relying upon libinput, this will allow tablet support for those running GNOME on Wayland in place of an X.Org Server. This is an important step towards making Wayland's input handling on-par with the long-standing code within the X.Org Server.