I am considering about a alternative spell system in place of spell slots.
As many classes have spell point pool, I try to combine them together.
rules:
A spellcaster class has a spell point pool equal to his level + key ability modifier. You can use it to cast spells or use class power.
If your highest spell level is 3rd or lower, the spell point cost for a spell is equal to its level.
If your highest spell level is 4th or higher, you cost 3 for your highest level spells, 2 points for those 1 spell level below your highest level,and 1 point for those 2 or more spell levels below your highest level.
How do you think about this.