I have been using Kalm, and it absolutely stunning. It is so good, but would be nice if it had a few more tweaks too. These include an option to make your own presets and save it as an xml or a custom config file, add other config files too, either from online or from local and add it as an extra preset, and compatibility for extra themes and animations (Like a guru meditating animation- as an extension - for yogic breathing), with online support if possible from store.kde.org. These are just what came up to my mind. Although you can put the others in your bucket list, The option to make custom configs and presets is a heavily needed addition. Please do add it.
Cheers,
Deon 