Traditional D&D style "Vancian" fire-and-forget magic is useful because it's easy to master mechanically, but difficult to master in play. You don't really need to learn a significant new mechanic to use magic, and though there is a high level of learning for spellcasters, it is a manageable sort of just-in-time learning as the magic-user player doesn't need to master all spells, just the ones in his or her character's spell book.
However, the drawbacks to me are a sense of danger and risk in using spells that seems to match the Sword and Sorcery genre (after all, spells incur no inherent risk to the caster such as failure or magical mishap), and a need for different types of characters to use very different mechanics in play, making it harder to teach new players how to play since learning to play one kind of character does not necessarily teach transferable skills to learn how to play another.
I have certainly thought about some tinkering with the standard Swords and Wizardry magic system. But at this point, I'm leaving the rules be since I think too much fiddling with the magic rules can upset the applecart, and at that point I might as well be re-tooling the system from scratch. In the end, I don't love Vancian spellcasting, but I think it's a tool that does get the job done with a minimum of new design and without needing to worry about the difficulty of teaching the system to new players.
So what is my problem? Fluff. Vibe. Feel. Mojo. The sense that this doesn't feel right. The solution? I have to be better as a DM of talking about the fluff side of magic, making it feel more dangerous, powerful, and eerie. Then get over the tinkering desire to make it "just right" for my tastes rather than workable for the game and the players.