Drawing upon inspiration from Roger Zelazny's Amber, here is a sort of an alternate way for prepared arcane casting to work - hanging spells.
The assumption is that a spell takes a prepared arcane caster too long to simply cast a spell from beginning to finish on the spot. A shortcut is to prepare the spell in advance, while leaving out a few key gestures, components, thoughts, and / or words to complete it once needed. The result is that the casting time for a prepared spell is the same as the rulebooks (standard action, usually, sometimes more, sometimes less. Depends on what the rules say). This also leaves flexibility in that someone could hold a slot open and attempt to cast a spell in full later on. Such a casting requires ten times the normal casting time (a swift spell becomes five rounds, a standard action becomes ten rounds, a full round action is the same, etc.).
This is only a preliminary thought, and has not taken the Arcanist into account yet. Spontaneous casters have their spells "burned" into them, and only need to use the "hanging" part to complete their casting.
Essentially this is the same as it always was, except that spells aren't forgotten as much as they are no longer prepared. The fluff has changed, not so much the mechanics of it.
Any thoughts or opinions?
It sounds like it would work well and it does make more sense then 'use and forget.'
I like it but one thing- for prepared casters why would you ever put the more ritual-y of the spells in a slot like auger or such? I would just fill my slots per day with the basic offensive/defensive stuff.