Kinematics
Hero
How much are you trying to improve?I'm definitely aware of that, but it's a pretty obvious pain point. I'm trying to see if there are other interactions I might be missing. Like "Rogue subclass X disproportionally benefits from having two or more attacks".
For example, for the rogue. Let's say he has a 1d6 weapon and 5d6 Sneak Attack dice. If base hit rate is 60%, then that averages out to 3.6 dice worth of damage.
Now we add 3 more attacks at 1d6 each. There's now a total of 9d6 at stake, and with the same 60% hit rate you might think that that increases things to 5.4 dice of damage on average, which is a 50% increase over the original.
However Sneak Attack isn't tied to the first attack, but instead to the first attack that hits. So it's actually 4d6 at 60%, and a 97.44% chance that at least one of those attacks hit and gives you the other 5d6 damage. Overall you end up with an average of 7.3 dice, or basically double the original damage.
Other "once per turn" damage sources, such as a Berserker's Frenzy, or someone using Great Weapon Master, will see a similar skew between the base attack and the chance of the once-per-turn damage, although usually with much less weighting than Sneak Attack for a rogue.
A lot of once-per-turn damage (eg: a PAM/Frenzy Berserker) might reduce the damage increase of going from 2 to 4 attacks to +50% damage. Some once-per-turn damage might give you around +75% damage. No once-per-turn damage (eg: sword-and-board, no smites) might give you the full +100% damage.
Meanwhile, on the cantrip side, that would seem to have a lot of side effects too.
For a basic Fire Bolt, it just means you have to roll an attack more often, which may slow things down.
If you have something like Elemental Affinity from Draconic Sorcery, where you get to add a fixed value once per damage roll, that means that instead of 4d10+5 damage (for a 20 casting stat), it's 4d10+20 damage.
For a cantrip which has non-stacking secondary effects (eg: Frostbite, cause disadvantage on target's next attack), you drastically increase the chances of landing that effect. For stacking secondary effects (eg: Ray of Frost, reduce speed by 10 feet), this can get overwhelming. This may be what you intend.