A couple of years ago (was it that long? damn) I ran a campaign that limited cantrips. I'm restarting one soon (had a session zero this past week). It lasted 10 session before my work schedule killed it. While there were some players who decided that the campaign was not for them, all of the players that started the campaign wanted to continue. The limitation was a consideration for the spell casters - every cantrip cast was a bit of a choice.
I run a very different game than standard 5e and I was completely fine with some potential players deciding this is not for them. But the game context for limiting cantrips was:
1. No experience from combat
2. Experience is from gold recovered and spent on non-advancement (carousing, philanthropy,bling,etc)
3. Encumbrance is simplified but strictly enforced (you need to be able to carry out that loot)
4. 1st Short rest lasted 10 min. The 2nd, 30 min. The 3rd (and final), 1 hour. (Rests also consumed food and water - back to that encumbrance issue).
5. Random encounter/hazard rolls every 10 minutes. (A random encounter only occurs on a 1 in 6, but other die rolls use up resources, environmental changes can occur, etc.)
The world itself was relatively low magic. Non-classed NPCs had access to rituals that were the main source of magical power mainly through saints, relics, etc.
Non-combat challenges and creative solutions to avoid combat were much more the focus. So it wasn't the damage cantrips that were the problem, but the utility cantrips that trivialized some challenges. And I'm OK with magic trivializing a challenge - that's what magic is for. But it should cost a resource; just like a non-magic solution may likely cost equipment, magic should be a resource that requires a thoughtful choice before it is expended.
I care more about niche protection than I do about balance. In a problem solving game that is less about your character sheet but your contribution to solving the problem the party is facing balance is less of an issue.
So here were my cantrip house rules:
CHANGES TO CANTRIPS
LIMITED AND UNLIMITED CANTRIPS
- In general cantrips are no longer unlimited.
- A spell caster now has Cantrip “slots” equal to their Proficiency Modifier plus their Spellcasting Attribute modifier. These are refreshed on a short rest.
- A spell caster can exchange a 1st level spell slot for their proficiency modifier (only) in Cantrip slots.
* Some spell casters (warlocks) may choose 1 unlimited cantrip that they can cast unlimited
times. They may only switch this choice of cantrip when they gain a level.
* Wizards may record cantrips in their spell books and switch out their prepared cantrips
during their Arcane Study.
* Any spell caster may substitute an Ability Score Increase to declare one of their cantrips
unlimited. A spell caster could forgo their initial increase to their spell casting attribute to
begin play with an unlimited cantrip.
* Unlimited cantrips can only be switched when the character gains a level.
CONCENTRATION
The following cantrips have concentration added to their
duration:
Light
Mage Hand
Message
Minor Illusion
These cantrips already required concentration:
Dancing Lights
Friends
Resistance
True Strike