rarely do I use a minion these days that doesn't have some kind of extra oomph.
try having minions explode in an aura 1, leaving a zone (noxious fumes perhaps?) that does level appropriate damage when a creature starts in it or enters it. it changes the movement strategy of the pcs quickly and makes it more interesting.
another favorite is having your minions attack everything adjacent to them when they die, berserker style. or mix the two; when you kill one minion it chain reaction kills the other which explodes into noxious gas. try using a ton of these on the table for an unpredictable explosion of violence.
make those little suckers count.