No doubt, Khotkeys is nice and stable soft. However I miss some very important features which can make interaction with the KDE much easier. After many years of using it I can point out what I (and, perhaps, not only I) need. Here they are in the order of importance:
Description: keyboard layout independent shortcuts.
Explanation: I have to use 2 languages described as two groups in the same xkbd file to keep all my shortcuts working under both languages. Therefore I use switching groups instead of switching layouts while the latter one is much more preferable in many situations. For ex. when you need to use more than 2 languages.
Suggestion: keycode-based shortcuts can solve the problem.
Description: Shortcuts consisting only of modifier keys.
Explanation: I cannot set a shortcut like "Ctrl+Shift" since one more key is always expected.
Suggestion: Including virtual "Release-key" may help. It will also allow to forget about modifiers (in certain situation, it's a pain to configure them) - the shortcuts like "Q+W+Release" or even "Q+W+E+R+T+Y+Release" will became possible. Isn't it great?
Description: Keyboard Shortcut -> Keyboard Input (simple) doesn't work with Languages others than English.
Suggestion: I use it to type some frequently used expressions so may be it's not a question to Khotkeys, but to Klipper and current Khotkeys functionality of this feature is enough to remap shortcuts and other small tricks.
Also Emacs style of shortcuts will make the Khotkeys much more attractive. This can almost work using Multi-key mode, but still the second key cannot be set to be a modifier.
Of course I understand that what I suggested here may require complete rewriting the Khotkeys so it's just my dream. Had I had enough knowleges I would do it on myself, but I am just a user.