Dying Earth style magic

[Whitewings]

From what I remember, and it’s been long and long since I read any of the original stories, wizards in the setting had to learn spells catch-as-catch-can. There used to be great libraries with thousands of spells available, but in these latter days, a wizard is doing well to have more than perhaps two dozen in his library.

I’m thinking that in addition to the use of spell slots, there should be no need for spell prerequisites to other spells, just very strict GM oversight of what spells wizard PCs start with and gain access to during play. Opinions, feedback, corrections of misrememberings?