Of note for minigiants complaint of novaing with slots versus the new format, a MotM devastator can fly and throw two fireballs and two lightning bolts in a fight/day. A Volo's slot based one can use his three third level slots and his one fourth slot among his prepared fireball, fly, lightning bolt, and ice storm spells. After those big guns the Volo's goes to scorching rays, magic missiles, and fire bolts at 7th caster level compared to the 21 damage MotM devastating bolt.
The new MotM format seems to roughly cut the listed spells in half and throw in more magical non-spell powers for their actual caster types