Thus, knowing that Holmes requires a to-hit roll with his version, I did not much look forward to having to deal with this reality. After spending some time with the actual verbiage of the spell, however, I think the Holmes version may very well be my favorite version of the spell:
A conjured missile equal to a magic arrow, and it does 1 die roll plus 1 point (2-7) to any creature it strikes. Roll the missile fire like a long bow arrow (Missile Fire Table). Higher level magic-users fire more than one missile.
Note that there are two different actions in this description. The missiles are conjured and they are fired. Note also that at higher levels, magic-users fire more than one missile but they don't conjure more than one missile.
The implication is that the conjuring and the firing can happen at different times — how else can a magic-user fire more than one missile if he only conjures one at a time?
Thus, a magic-user could spend his down time prepping a quiver-full of magic missiles (and I personally would limit the possible total amount to one quiver) that could then be fired off as necessary. Given that Holmes deals with levels 1-3, this implies that a magic-user will be able to fire an additional missile per round at 4th level and every 3 levels after that (three missiles at 7th, etc.). These missiles would be all be one-use items that could only be fired by the magic-user who conjured them.
Since it appears that magic-users start off with all the 1st level spells that they know based on their Intelligence, this allows a player to be more creative with their low-level spell choices. One need not go the offensive route. With twenty magic missiles ready to go off whenever they are needed, a player is free to choose a utility spell instead.
This vision of the spell becomes especially evocative when one thinks of the Elf. What else would a bunch of elves have in their quivers other than a score of magically conjured arrows?