Martin Gräßlin has been spending most of his time recently focusing upon the KDE input support for Wayland and better supporting libinput. There's been a lot of code clean-ups and bug fixes as well as bringing input features closer to parity between X11 and Wayland.
For now until the KDE Plasma 5.6 release, Martin will be working on more bug fixing. Details on the latest KDE Wayland input work can be found via this blog post.
Plasma 5.6 is scheduled for release around 22 March. Following this next major release, Martin is looking to return to XDG-Shell support for KDE on Wayland as well as making multi-screen work correctly. There are also some potential KDE Wayland work items for this summer via GSoC such as layered compositing, Wacom tablet support, window tab support, and running KWin/Wayland in a Docker container.