It honestly depends totally on which Demigod you are playing..
UB don't bother doing anything but the demigod (unless its Sedna then its priests then Sedna) Ooze will most happily kill the minions for you..
Sedna straight to the demigod.
TB (so many AoEs its like what creeps/minions?)
Regulus straight to the demigod (fortunately mines and MoTB both kill minions too)
Rook (?)
Oak smash minions when necessary for heals, smash enemy demigod
Queen (so many AoEs its like what creeps/minions?)
Erebus straight at the demigod too..