End user configuration is definitely planned - my philosophy is 'get it working, then make it pretty and configurable'.
The button selection is a layover from its early days, when I used left-click for something else. I think
Left - to drag
Right - popup small options panel
Left+Right - toggle lock
Is probably the more intuitive selection.
Options to change layout direction and label display are in the works.
Hadn't thought about keeping the docker open - this is dangerously close to turning the dock into a bar addon! But now you've brought it up, I can see the use to it.
Regarding the allcaps - I wanted something that wasnt likely to be used by something else - it's still early enough that I can change it if you really feel a need to.
With a relatively simple API, if someone else wants to write something that duplicates the functionality in a different way, they are free to do so, and if they recreate the API in the own addon, there should be little to no extra for work for addon authors once they add in support once.