Is this house rule to balance the college of whispers bard balanced?

Question

As a player and a dungeon master, I feel like the Psychic Blade of the college of whispers bard is really unbalanced regarding the Sneak Attack feature of the rogue.

First of all, they mostly does the same amount of damage... But the Psychic Blade does psychic damages, where the sneak attack's damage type is the one of the weapon (bludgeoning, piercing or slashing). The problem is that psychic damage is one of the less resisted type of damage, where bludgeoning, piercing and slashing damages are the most resisted type of damages.

Second, Psychic Blade is way easier to trigger than Sneak Attack, only needing to spend a Bardic Inspiration (which come back on short rest after level 5) and you have it, where Sneak Attack require advantage or an ally to use it.

So, looking those elements, I decided to replace the cost Bardic Inspiration of Psychic Blade with a condition. To use the Psychic Blade feature, you don't need to spend a Bardic Inspiration, you need advantage on a type of charisma check against your target, be under the Mantle of Whispers feature effect, or the target have to be frightened or charmed before the attack hit.

To me, it keep the flavor of a bard that is also a killer, still synergyse with the others college of whisper features, but make it a little bit harder to the bard to have the Psychic Blade. But is it balanced?

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To clarify:

• "advantage on a type of charisma checks against your target": e.g. the friend cantrip, be friend with it, etc...
• Mantle of Whispers: the 6th level of college of whisper bard feature. Now that I re-read it, maybe I should remove that part in the rework, or make it end if you deal damages as part of the rework.

Answer 1

Sneak Attack is better than you think

In order to land a sneak attack, the rogue needs to be making an attack with advantage, or the target needs to have another enemy within 5 feet (and that enemy isn't incapacitated, and you don't have disadvantage), while you are using either a finesse or ranged weapon.

This sounds kind of tricky, but let's look a little closer. Firstly, a rogue is almost always going to be using a finesse or ranged weapon. Rogues often have a lot of dex so finesse is great for them, and ranged weapons will keep the rogue out of harm.

In a party there is usually at least 1 other melee character, so the rogue will always have a guaranteed source of sneak attacks just by hanging around them.

The rogue can also use their bonus action to hide (rogues often have high dex, so hiding is no big deal), giving advantage and sneak attack. The ease of accessing both advantage and sneak attacks is what powers many rogues.

In combat a rogue will almost always sneak attack for every single attack. What's more, the rogue could even do this more than once in a round, by using opportunity attacks. Even if the rogue didn't have sneak attack, they would probably still be hiding to gain advantage, and working together with other melee characters.

Psychic Blades is worse than you think

While the rogue is out there spamming sneak attacks, the bard is a lot more limited. Firstly, they are limited by their number of bardic inspiration die. With 20 charisma the bard only has 5 uses per rest. That's great if you have 1 fight per rest, but otherwise it's extremely limiting. What's more, if you use your inspiration die for damage, you can't use them for, you know, inspiring people.

Psychic Blades also does not scale as nicely as sneak attack, which isn't a big problem but it will mean that half the time it's dealing less damage.

Bards don't have a lot of feature support for melee combat either. They don't have cunning actions like rogues, and they have to split their attributes between cha and str/dex to be effective. That tax and lack of feature support makes them less effective. Even if they had access to sneak attack, rogue would be superior.

While psychic damage type isn't commonly resisted, a rogue can equip a magic weapon and bypass most physical resistances. By the time this becomes a problem, the rogue probably already has the solution.

Answer 2

If it ain't broke, don't fix it.

I think your rewrite of the psychic blades ability makes it significantly stronger, and your reasoning doesn't add up.

#1: Prevalence of Resistances

You are correct to observe that resistance to psychic damage is much more rare than resistance to slashing, piercing, bludgeoning, unless we break the latter into its two categories. Resistance to all slashing, piercing, and bludgeoning is far more rare than resistance to non-magical slashing, piercing, and bludgeoning. The moment your rogue gets access to a +1 magical weapon, this particular argument of yours no longer applies.

#2: Ease of Use

You are correct to observe that psychic blades is easier to use, but this is only the case when you have remaining bardic inspiration. The reasoning you give here is already baked into tying psychic blades to a limited resource. A 20 charisma 5th level Bard (which is very generous) can use up to five bardic inspiration per short rest. It's easily conceivable for a rogue to use sneak attack every or nearly every turn of every combat without expending any resources at all. You bonus-action-hid last turn? Sneak attack. Your paladin is in melee with your target? Sneak attack. For free.

And you must further consider the opportunity cost of psychic blades. You burned your inspiration on psychic blades? That means no bardic inspiration for any of your allies to get those precious extra points to beat that tough DC.

#3: Your proposed solution

You propose, "to use the Psychic Blade feature, you don't need to spend a Bardic Inspiration, you need..."

(1) Advantage on a charisma check

You clarified this in comments saying "I mean that you can use it if something gives you an advantage on checks that involve charisma and that target the thing you want to target (e.g. friends give you advantage on charisma check against a target)".

So I burn an action at the start of the fight to cast friends. At the cost of a single action, I get to use psychic blades every turn until my target dies. This is part 1 of "make psychic blades more easy to use".

Additionally, there exist magic items that just give permanent advantage on a type of charisma check, such as Far Gear (Acquisitions Incorporated, pg. 221). Being attuned to an item such as this would mean permanent psychic blades at no cost whatsoever.

(2) Under Mantle of Whispers

The setup for this is pretty tedious, but it actually works against you. Mantle of Whispers remains "until you use it or finish a long rest". As long as you don't use the ability's primary feature, you just got psychic blades for free every turn, even more available than the rogue's sneak attack, without expending any more resources.

Unless you meant "you have used the shadow and are now in the disguise". This needs to be clarified. Still lasts an hour. Still get psychic blades for free for a whole hour. This is part 2 of "make psychic blades more easy to use".

(3) Target is charmed or frightened

Now you're just adding more conditions to make psychic blades go off more than it ever did as originally written. This is part 3 of "make psychic blades more easy to use".

A Whispers bard with this rewrite is almost certainly going to use psychic blades more than he ever did when it was tied to his uses of bardic inspiration.

Conclusion: Your house rule takes a non-existent problem, and makes it into a very real problem by doing the exact opposite of what you intended.