I was listening to the Dead Games Society podcast on the drive to work this morning and they were talking about Holmes Basic and Magic Missiles came up as a topic.
In Holmes, the magic user needs to roll to hit with MM, and as all weapons do 1D6, and MM does 1D6 in Holmes if I recall correctly, why would one even bother to memorize the spell? Just throw a dagger with the same chance to hit and damage.
As for the Sleep spell, it's always been the low level nukes, but that's a topic for later.
So, do you prefer your magic users to roll for their Magic Missiles?