I think that there should be some mechanic to make charge times decrease as characters level up. Because as characters speeds level up the relative charge time increases, even if the actual clock ticks remain the same. Tying charge time to speed would make it so spells don't get 'slower' as your characters get faster. It could also create an interesting mechanic where you can choose to gear for MA to get more damage, or for Speed and have your spells cast quicker.