What's wrong with it? It gives you guaranteed damage, provided the target isn't immune to your cantrip. Just use cantrips that require saving throws rather than attack rolls and you're golden! If you're fighting enemy wizards, forcing a concentration check without having to use a spell slot seems pretty powerful to me.
For one thing, none of the evocation wizard cantrips have saves -
fire bolt and
ray of frost are ranged spell attacks, and
shocking grasp is a melee spell attack. The only wizard cantrips that have saves are conjuration (
acid splash and
poison spray). Sure, there's no particular
need for them to be evocations, but it's silly if the Evoker has an ability that's only useful with Conjuration spells.
That said, the Elemental Evil Player's Companion helps a bit in this regard, adding
frostbite and
thunderclap as evocation cantrips with saves.
