Instead of choosing one of these options, I've thought of a new house rule for T&T spell casting that simplifies the current 'point' method:
Wizards, Rogues, and Warrior-Wizards may cast a number of spells per day equal to his/her Strength or Wizardry attribute. Each level of spell increases the casting cost by 1 point, so a first level spell costs 1 point, a second level spell costs 2 points, and so on. A day starts after the spell caster gets at least eight hours of uninterrupted rest (no moving, no fighting). Spells that are cast do not vanish from memory and may be cast multiple times. So if you have a WIZ of 15, you could cast Take That You Fiend 15 times in a day as long as you cast no other spell. When using the Strength attribute to power magic (1st-5th editions), Strength is not reduced and personal adds are not lost from casting spells.
Benefit of magic staffs: A magic staff increases the number of ST/WIZ points available to a Wizard each day equal to 1D6 + Wizard level. The die is rolled at the start of each day making the benefit of the staff somewhat unpredictable. Makeshift staffs can only be used once before becoming worthless.
Casting lower level magic: Wizards may cast lower level magic at a cost reduced by an amount equal to Wizard Level minus Spell Level. The base cost is always 1 point. So a 3rd level Wizard can cast first and second level spells at a cost of 1 ST/WIZ each. A 10th level Wizard can cast a 7th level spell at a cost of 4 ST/WIZ.
Powering up spells: A wizard can cast some low level spells at a higher level to greater effect. The spell simply costs a number of ST/WIZ points equal to this effective level. So a third level Take That You Fiend costs 3 points.
To me this house rule fits in well with T&T's basic KISS strategy. This approach seems to work out in my mind, we'll just have to see how it works in practice.