Lots of people have complained they felt the remaster hurt spell schools for wizards. Others point out that there is an implied flexibility that GMs can allow other spells not on the list to be considered part of the school list. Others point out that GMs always have such flexibility and that it not being in the rules, means people can assume they won't get such flexibility.
I think one easy step to insure that they get some usability out of their school curriculum would be to allow any wizard to when they advance to being able to cast a spell of a new rank, to be able to pick one wizard spell they already know of their old highest spell rank(or maybe option for lower) and add it to what will be referred to their personal curriculum (or could be called minor curriculum) and gets to be treated as a curriculum spell.
Next, have 'alternate' casting versions of at least one of the cantrips and 1st rank spells in each of the schools curriculums that are in line with the Spell Trickster Archetype. I'd even suggest having some higher level spells as well, but allow the wizards to cast the spell the normal or variant way when prepared. The wizards would automatically learn a new curriculum from their school at specific levels.
The other fun part, is that variants would also be content that the Spell Tricksters could poach from, but would be paying feats for them for the liberty to grab ones more independently.
Other thoughts that come to mind would some variant spells be 'uncommon' spells that could be picked up by other casters, but in such cases they would have to learn them as an independent/separate spell.
This makes me also wonder, is Glass Shield actually a variant of Shield that expanded out to the Primal tradition as a separate spell for instance.
With that in mind, you could potentially even create 'related-spell' combos, that a particular curriculum, that the wizards can select the combo, and would be able to at time of casting select either of them.
For instance, if there were a Necromantic school, a school meta-spell might be Circle of Life, which is defined as a choice of Heal or Harm chosen at the time of casting.
I think such a meta-spell could be defined for each school potentially. But I think those would probably be more powerful than variant spells so wouldn't be available choices for Spell Tricksters to poach.
So the idea here is to unravel the theming of the curriculum slot?
I think thats what many of the people on these threads have expressed a desire for.
You could just remove curriculum as a restriction entirely on the fourth slot but make learning spells the place where restrictions happen.
So at each level a wizard automatically only learns spells from their curriculum plus 1 spell outside their curriculum. This represents what a wizard was exposed to. In fact they should already have all schools spells in their spell book but they obviously cannot use those spells for lack of high enough rank slots.
At level up they only gain 1 new spell of their choice not 2 and all curriculum spells.
They have no additional restrictions on learning from scrolls so they can still learn whatever they want from exposure but what they learned from school and gain at each level automatically is more restrictive.
I mean idea they decided behind the mechanics of curriculum was that having gone to school the wizard actually gained capacity beyond 3 slots gaining a 4th slot that is restricted to curriculum.
The difference here is the idea that the wizard is entitled to 4 slots not 3. If that thought wasnt there there would be nothing to believe needs fixing right?