while in Dark Souls you have a limited number of castings for each spell and if you want more casting, you better get another copy of the spell. it is harder to abuse but goddamn you need allot of spell slots just so you can use one spell a useful number of times and you had to play through the entire game again to get those extra castings, yeesh, what a chore!
what if Dark Souls Deux was a sort of hybrid system? you only need one copy of each spell because it relies on mana to cast. however, there wouldn't be such a thing as spice because your mana bar would regenerate slowly over time (like stamina only much slower). this might effectively make casting spells work allot like swinging a sword. as you'd have to manage you mana the same way you have to manage your stamina bar.
i expect to be torn apart for this, but i like it rough so bring it on.