I have a slightly different meaning in mind when I say customizable. I would want to add commands on a whim and try them out in the bar. If I had to spend more than 10 seconds adding it then it wouldn’t work for me. I am constantly adding, removing, and rearranging apps on my windows taskbar. Of course they all have icons.
In any case, this is definitely on my to-do list.
Yes, in order to pull this off it would need a simple list of all commands to choose from, drag and drop rearrange, and easy delete (drag them off bar?).
I don’t see these ideas as competing. You have a ready-to-use pretty bar. Hiding and possibly rearranging is all one would want from your bar.