I think Vancian magic could have been done well if it had been more Vancian.
Having just finished the book, I strongly disagree.
People talk about Vance's system like it was mostly about memorization of spells.
From my read, it was not. It was mostly about KILLING ANYTHING WITH MAGIC. Vance spells, 75% of the time in the book, either kill you outright (or the equivalent) or are avoided or blocked outright. Almost no wiggle room. Almost no utility. Vancian magic was mostly save or die.
In Vance's Dying Earth books, a wizard could essentially cast a handfull of death spells per day. And it was never dozens and dozens of spells...always a handfull at best, and usually only 3-4. Most were various gruesome ways of killing someone (teleporting them miles below into the earth, filling them with holes from multiple laser shots, etc...). A few were utility, like flight or invisibility (Phandaal's Mantle of Stealth) or time stop (Spell of the Slow Hour) or endurance (The Charm of Untiring Nourishment). Some others seemed like utility were actually similar to auto-kill, like summon something to fly a person across the planet (which in D&D would be nearly the equivalent of death, if a character is separated by a planet's width of space from the party and having no way to return).
So no, we do not want a system MORE like Vance's system. Vancian wizards are godlike beings that could slay any Fighter on a whim with a single spell if that Fighter does not have protection from magic.