Hi,
I have introduced a new way of casting spells for my version of the Wizard Quest. SirRick, I think this comes close to your original idea.
Here is the relevant excerpt:
9.3.2.1 Mages’ Guild
In this guild, the mage can learn the skill ‘Inner Power’. This skill represents a completely new magic system. ‘Inner Power’ grants the mage 5 magic points for every point of intelligence. Plus 3 Power Points each for the status titles “Hero”, “Master”, “Grand Master” and “Lord”, and 3 Power Points for each extension learnt. These are consumed when a spell is cast. When a spell is cast, the card is no longer discarded as before; instead, the wizard deducts the required Power Points from their supply. Each spell costs a certain number of points. However, the following rules must be observed:
• Each spell may only be cast once per round.
• Each spell may only be cast a limited number of times per quest. This number is determined by dividing the current Intelligence points by 2. Odd results are rounded down. The Counter-Spell can generally only be used once per quest.
• Spells marked with a + cost the indicated number of points only when used for the first time in a quest. Each subsequent use costs one point more. For a ++, the number of points increases by 2.
• Status-altering spells (e.g. Bravery, Granite Skin) can only be active once at a time. As long as a hero is under the effect of such a spell, it cannot be cast on any other hero.
If the wizard’s points drop to 0, his magical power is exhausted and he can no longer cast spells. However, there are potions with which he can partially or even fully restore his magical power. Learning this ability costs 700 gold coins and cannot be undone. If the wizard wishes to return to the old system, he must visit the guild again and relearn the old system there for 300 gold coins.
The following power points are required for the individual spells:

I had the list and the excerpt from the rules translated online. Please forgive the errors in it.
Best regards, Thrasher79