I don't know crap about 4th ed, but I do know the "higher-level caster hits multiple lower-level targets" function of Magic Missile in 3.x and earlier is handy. There's a sweet spot around 5th level where you can thwap three different enemies (you get an extra missile every 2 levels 'til 9th.) Each missile is 1d4+1, and there's a decent chance an encounter for a 5th level party will be a group with individuals wimpy enough that ~3 points of damage still matters. Or you just hit that one guy with a stupid-high AC.