I defiantly hadn't planned the defensive play to fit this nicely with the theming on a conscious level, but there may have been something sub-conscious that lead to this design. At first I had considered just letting you hurt the enemies with the left click, part of why it costs so much spin, but something felt off about it and so I hard learned into the concept of reflection only.
In terms of balance, to be completely honest; the spin has always been intended to be used like 90% of the time, but does take some time getting used to. And as the dev I rarely even use the left click. Thinking back on it I should have switched the controls so that spinning was left click and the throw was right click. That way it'd make more sense which you are intended to use more. and yes the throw may be too costly.