Just thought of another aspect; sometimes a change is about the events, e.g. change from tap to touch start, keeping the same actions. (It would be a bit of work to add reordering features to the UI, without messing it up. Its clean and simple as it is now.)
And talking about events; would it be useful to have 'on focus'?
To support keyboard, touch and mouse interaction in the same user interface it seems to be about working with focus – and make the styling of focus to be similar as of 'down', 'touch start' etc. Are not Google Material on the way in that direction?
I've added external CSS for focus. Works. Except for styling the border of a circle, in my experience.
Animated effects for 'on focus' is harder. Would prefer to define that in timelines.