I would like to have the possibility to add more actions or custom actions in the title bar via the kcm module for window decorations. I miss extra buttons for vertical maximize, horizontal maximize and one for the kwin script "Exquisite". It would be cool to be able to link all possible commands to a button in the title bar.
Unfortunately with the presence of so many client-side-decorations this wouldnt' work in practice. We would create a whole architecture only to have things not available in several important apps