I for one don’t like to use controllers, I can say that yes I have a phone but that does not mean I want to game on it.
Yes almost all build in PoE are like that, when V2 of PoE is released it will have an option to effectively auto cast all your aura skills, there by making it easier to play a one skill wonder build.
Yes not to mention that playing with too many keys can have us Older types having aching hands after a few hours.
I don’t mind if other’s want heaps of key options I will try to keep my build to a way I like to play.
And as stated you can only spend that resource once, untill you get it back.
I refer back to t maybe a limit of the Keyboard.
A Keyboard only lets you use 2 key presses at any time the third will not behave as expected.
It can also stop all input when doing so, If they have already tested this in house with the older games and found that it is a problem without a viable work around, it becomes easier to just set the 6 key/skill limit.
As I see it the best option is a toggle to give you more skill buttons use it or not, you pick.