I don’t have enough time so I’ll break it.
As for some supportive abilities like heal puls of Night or armor up of Cain and etc, sometimes it is annoying and time consuming to find the target ally to allocate the subject abilities which may cuase suffering the penalty while you’re searching. The fact that the allied heroes are in line or behind you exacerbates the injured time.
Here is a suggestion. Let the people use drag and drop trick simply by dragging the icon of ability on the pic icon of the target heros like below.
I know operator heals the hero with least remaining health and abovementioned is not applicable here, But as for shortage of time I just made up above to illustrate further.