The dbus support for KRunner is great for users who don't know C++ and makes writing the plugins a lot easier.
But the KCMs for the runners have to be written in C++.
My idea is that the users can use an existing kcm and configure a .desktop file for it.
In this file they can expose some basic configuration defining trigger word and making this trigger word required.
And maybe later on some additional widgets.
This will make it also very easy to add basic configuration to an existing plugins and
it will avoid duplicate code.