UPDATE: I thought I had something, but as soon as you exit the powers menu it goes all back to normal, there is probably a check value somewhere - maybe with cheat engine or a debugger someone can figure it out, so I will leave this here. Should have tested it better.
You cannot change the cool powers anywhere that I could find, but a little outside the box thinking and I found out how to get unlimited runes.
Set all the passive powers like -30,
That way, when the game does it's math, your current runes will always be greater than -30 (because they said "current_runes >= cost_of_ability" instead of "current_runes >= cost_of_ability && current_runes >= 0" ) the game will deduct "-30" from your current runes, which will in turn add 30 runes.
The game will reset the runes to 0 after every transaction, so you have to alternate, passive ability, for power, etc - so you may not be able to get them all. Not perfect, but close!