As a D&D 5e GM and ex-D&D 3.5e GM, I have found that cantrips are too strong:
- After a certain level, they deal more damage than some level 1 spells.
- You can use them indefinitely.
- It makes a spellcaster almost never need a weapon (and so "weapon-needing" classes become bad).
The first problem leads to the other two, so in my game I have created a house-rule to prevent cantrips becoming more powerful by levelling up.
For example, the description of fire bolt says:
You hurl a mote of fire at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 1d10 fire damage. A flammable object hit by this spell ignites if it isn't being worn or carried.
This spell's damage increases by 1d10 when you reach 5th level (2d10), 11th level (3d10), and 17th level (4d10).
My house-rule would remove the increased effect at higher character levels, so that the description merely reads:
You hurl a mote of fire at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 1d10 fire damage. A flammable object hit by this spell ignites if it isn't being worn or carried.
Will changing all cantrips in this way be balanced?
I want to make spellcasters less overpowered, so that non-spellcasting classes can shine again.
My problem is not just the cantrips, but the fact that spellcasters have super-powerful spells that make them superior to some classes. In all other versions of D&D that I have played, they were "balanced" by the fact that once they have used up all their spells, they're not as effective (I said "balanced" because they are almost all Tier 1/2 in other editions). But now, they can cast super-powerful spells and still be at least not useless after using all their spells. (So they were the better classes before 5e, and became even better than before in 5e.)
Best Answer
Maybe instead of trying to compare spell casting classes and martial classes, try looking at the same class at different levels.
To just look at cantrips we could assume all spell slots have been used. We could also look at a spell casting class that relies heavily on cantrips, the Warlock. Both Warlocks have the Eldritch Invocation Agonizing Blast.
Example of imbalance
Level 20 Warlock and a level 2 Warlock vs 2 CR 1/4 Skeletons with 13 hit points. Both Warlocks hit with Eldritch Blast. The 20th level Warlock rolls a 1 on his damage die + 5 extra damage from Agonizing Blast (his Charisma mod) for a total of 6 damage. The level 2 Warlock rolls a 10 on his damage + 3 extra damage from Agonizing Blast for a total of 13 damage.
In the above example both Warlocks hit but only the level 2 Warlock was able to take out his Skeleton. It may seem unfair to give the level 2 max damage and the level 20 minimum damage but the odds are equal for both rolls. An unbiased example would have the level 2 dealing 8 points of damage average while the level 20 dealing 10 damage average. Even in the unbiased example the level 20 Warlock cannot on average, drop the 1/4 CR Skeleton to 0 hit points in one turn. The same level 20 Warlock without the house rule would do 40 points of damage on average. With 24 points of damage minimum and 60 points of damage maximum.