To me, a wizard that can chuck magic missile all day is a serious deviation from what D&D is. The warlock is a special case, and an interesting class in its own right, but that's not what I would do with the wizard. The paladin can cast evil, the warlock can blast, that's fine, that's their schtick. The suggestion made by Monte substantially changes the face of D&D; a world in which 1st level wizards can chuck spells all day is NOT, by any stretch of the imagination, Greyhawk, Mystara, the Forgotten Realms, Dragonlance, and especially, Dark Sun. Such a world is so far removed from its sword-and-sorcery roots that a greatsword wielding barbarian would actually be out of place; what role could such a character have as a protagonist in a world of omnipresent magic?
Logically, you'd then need all-blasting-all-the-time versions of the the duskblade and spellsword, variations on Hideous Blow and Arcane Strike, and so forth. Nine Swords would fit right into that scheme.
A knight with a lance on horeseback? Ha! That poor animal would get shot out from under him in two seconds. So now we need spells that protect mounts...
The whole thing would turn into a Magic: The Gathering level attack/counter/counter-counter nightmare.