@graesslin, after looking for couple of hours on kwin, kde-workspace and some others repositories i come with idea:

• KWin::Rules will use list of effects(maybe special X-KDE-ServiceTypes) to generate map/vector of all available rules
• every Rule will provide/implement:
  • "unique" identifier, for example: blur; that is going to be used to identify it in KCM and KWin::Rules
  • KCM(just the row or whole tab bar) for kwinrules.
  • special interface which is going to be used by KWin::Rules with virtual methods like: void read(KConfigGroup&), void write(KConfigGroup&), void apply(Rules*), apply(Client*), void discard(Rules*), etc

Fixed formatting.