I personally see Vancian magic as one of D&D's defining features, something that sets it apart from other FRPGs. Something that adds to its unique character.
Not everyone feels likewise, I know. Lovers of Vancian magic may even be in the minority of D&D players at this point.
So for those who really despise Vancian magic as much as some clearly do, I have to ask: What is it about D&D that attracted you to the game?
I was given the Moldvay Basic set as a gift when I turned 11. I had heard of D&D before that, because I was an avid purchaser and player of Fighting Fantasy Gamebooks, which were published by Puffin and therefore carried, at the back, advertisement copy for the Puffin book "What is Dungeons and Dragons?" I hadn't heard of other fantasy RPGs at that time, and the family friends who gave me the game hadn't either - they bought the game for me on the recommendation of a toy store salesperson ("What would you recommend for a bright and bookish 11 year old boy?").
What attracted me to Fighting Fantasy books, and then to D&D, were the same things that attracted me to books about knights and castles (both fiction and non-fiction), to super hero comics, and to movies like Star Wars and Excalibur: pleasure in the themes and the tropes. As a boy I probably could not have articulated exactly what that consisted in, but now I would say it is something about the pre-modern, romantic ideal.
I also enjoyed the gameplay aspect, but the themes are more important. While, by the standards of a typical person, I have played a lot of M:tG, for instance, I have never been the least inclined to drop fantasy RPGs for fantasy CCGs, which have the gameplay and the tropes, but not the thematic dimension.
Anyway, Vancian casting is utterly irrelevant to any of this. As a mechanic, I tend to find it a nuisance - not so much the tracking of usage, which is easy enough, but the selection process, which bogs down play (even with the 4e wizard in my game, I find it causes needless drag for little apparent benefit). At low levels I regard it as obviously flawed, because low level wizards don't really
play as wizards, but I have never played nor GMed a pure wizard PC, despite many years of playing and GMing B/X and AD&D.
For aesthetic reasons I have long preferred the more focused spellcasters of Rolemaster to the generalist D&D wizard, and I like that 4e produces somewhat less generalist spellcasters (though power bloat is, over time, diluting this). That said, I am hoping to run BW some time in the future, and it has generalist casters - but on a fatigue mechanic, not a Vancian one.
I hope that gives you some answer to your question!
