Is my College of Poems bard subclass balanced?

Question

College of Poems V.1

You have been trained in the art of poetry, you have gained heightened sight and knowledge. Your poems can invigorate your allies, or torture your enemies. The power of poems is something that you have harnessed and your words shall always be heard.

Poetic eyes can see a disguise, those of this college have quite powerful knowledge. Your poems give life and your insults cause strife. You cut your enemies down like a knife because your strength is rife, and may you never be solivagant.

True Rhyme

At level 3, when you take this college, you gain the power of rhymes. You can choose to make your spellcasting focus something that you can write with or write on. You learn Thieves' cant, and druidic. Also, you can add your charisma modifier to any insight or arcana check.

Hightened Imagery

Also at 3rd level, you can see, and describe anything you need. You gain 5ft of Truesight, and once per long rest, when a creature tells you about a place you have not been to before, you can make a DC 13 Arcana check to see if you can tell some main features of the place (Plants, types of creatures that live there, how the entrance looks, etc.)

Repitition

At 6th level, once per long rest, you can spend an action repeating a word of your choice over and over again. One creature that can hear you must make a Wisdom saving throw or take your Profciency bonus times d10 psychic damage. If this word has a specific theme, such as flame being fire, then that is the damage type of the spell instead. (Does not work with force damage.)

You can do this twice per long rest at level 11, and 3 times per long rest at 18th level.

Alliteration

Beginning at 14th level, your poems come into full power. Once per long rest, you can spend an action alliterating. You can use alliteration to harm your opponents minds. You must actually speak several words using alliteration, and the creature takes an amount of psychic damage equal to the number of words said multiplied by 2, to a maximum of 50 psychic damage, which you may divide up to 5 creatures that can hear you.

If this words have a specific theme, such as "flame" being fire, then that is the damage type of the spell instead. (Does not work with force damage.)

If the words have several different themes, such as "heat, heaven, hell", being fire, radiant, and necrotic, then you may split the damage among those damage types in whatever amounts you wish. (Does not work with force damage.)

Answer 1

True Rhyme

This is fine. Similar to the Fey Wanderer level 3 power, but scoped to two specific skills. Not sure why you get Thieves' Cant or Druidic (how is this related to the core theme?), but that's a role-playing thing more than anything else, so it doesn't affect balance.

Heightened Imagery

This is ridiculously overpowered. The True Seeing spell is unavailable until level 9 for any other class, and you just gave a permanent version of it, albeit at short range, at level 3. Permanent 60' Truesight is an epic boon, and while this is only 5', it lets you see everything in that range, all the time. The DM can't have any form of magical social intrigue, ever, because shapeshifting and illusions won't work at close range. Stuff hidden in the ethereal? You just see it if you pass by. The link goes into more detail, but short version is, always on Truesight is too good.

The kicker ability is just weird; you're told about a place, and just know random other factoids about it (with a DC13 Arcana check, and being able to add Cha to Arcana rolls, you're almost guaranteed to make this check in short order, unless the character just dumped Int)? Why? How does this fit the theme?

Repetition

Not all that great, except when the variant damage type lets you target vulnerabilities. It's strictly weaker than a Warlock with Eldritch Blast + Agonizing Blast; when you first get it, it does 3d10 (avg. 16.5) damage a limited number of times, where a same-level Warlock with Cha 18 can do 2d10+8 (avg. 19); at high level, it's 6d10 (avg. 33) vs. 4d10+20 (avg. 42). Sure, it's a little more likely to land (Wisdom saves are typically a worse defense than AC), but the expected damage is lower, it's all or nothing, and it's limited use. Granted, Warlocks are Eldritch Blast machines, it's intentionally the peak of cantrip damage-dealing, so it's an unfair comparison, but even comparing it to normal Bard cantrips (or to a Bard grabbing it via a feat or class feature) it's not enough better than Eldritch Blast without agonizing blast or Toll the Dead or the like.

Basically the only benefit to it is being able to narrowly target enemies with damage vulnerabilities with the damage they're vulnerable to, but the flavor of the ability doesn't make any sense for that. For both this ability and the next one, it's flavored as a mental attack, and mental attacks do psychic damage, not "whatever the creature thinks the attack is" damage. Phantasmal Killers deal psychic damage even when the target thinks they're being rended by claws, or set on fire. And a mental attack against mindless (psychic immune) undead makes no sense. If poetry can rewrite reality, okay, sure, that works, but the flavor needs to support a non-mental source of the damage. There's no reason to restrict force damage though; chosen non-force damage is more powerful than force damage, and frankly, if they don't apply this to enemy damage vulnerabilities, the power is weak enough to be ignorable; if they just giggle at using force to bypass resistances and immunity, they've wasted the ability.

Alliteration

The bard will always precompose alliteration dealing 50 damage. So just call it that. Otherwise, this is essentially a slightly lower expected damage version of Hurl Through Hell (10d10, avg. 55) with a variable damage type, that always hits, but costs an action (where Hurl Through Hell is an add-on effect to another attack that already hit). Granted at the same level even. Main issue is the vulnerability one; if your players use it right, this is a fixed 100 damage, no attack roll, no saving throw. That's... a bit much.

Summary:

• Your theme is inconsistent: attacking the mind, doing non-psychic damage is not a thing in D&D 5E, and many of the add-on abilities at lower levels don't fit a coherent theme either.
• Truesight should never be an always-on power in early tier play (even 5' Truesight is basically a capstone ability).
• Variable damage types are exploitable (but without the exploit, one power is too weak, and the other roughly just right), and essentially unheard of (at least not with this level of flexibility).
• Not a balance thing, but a note: Just dealing damage is kinda boring. Players who want to blast their enemies play Sorcerers and Warlocks. You made a Bard who specializes in magical poetry a blaster. Surely poetry should do something more interesting and thematic than just "blow things up with rhythm"?

Answer 2

This needs work to balance the various features

Important are the lower level features, as most play in D&D happens in tier one and two. It's less important how balanced your level 14 feature is.

• Heightened Imagery is too powerful. Truesight is a level 6 spell effect, for just one hour and 25 gp to boot. Having this on all the time, even at short range, will invalidate a lot of adventures, especially at low level, where secret doors, illusions etc. are supposed to be real challenges. This is not an effect you should have access to at that level. What's more, it will drive undesirable behaviour: now your character has to canvas every room to make sure they benefit from the feature.

• True Rhyme is breaking bounded accuracy even worse than expertise, as it can be combined with it. Having two skills that essentially always succeed may not be game breaking (even for good ones like Insight and Arcana) but certainly is strong too. The rest is more of a ribbon (I've next to never seen Druidic or Thieve's Cant seen in game, and what you use as your focus does not matter much -- typicaly for power play, you want a focus that is otherwise useful, like a staff, wand or such, not a piece of paper).

• Repetition: the whole thing about non-Force damage does not do much, other types like radiant are nearly as little resisted as force, so it is mostly about using it against a vulnerable creature, which are rare. You could simplify that. The damage is maybe a bit higher peak, but a college of Lore Bard, can pick up magical secrets to deal 2d10 force with eldritch blast at will, instead of one time or a few times per day, and can pick another strong spell on top. So this is relatively weak.

This leaves us with one overpowered, one middling, one weak feature in the relevant levels. Having one feature that is too strong, and one that is too weak is not a good way to make things balanced.

Finally, Alliteration could need better wording and mechanically is cumbersome. Currently it appears you can just make up a string of 25 words that start with the same letter, to deal 50 damage witouth save or to hit. That is not game breaking on level 14 (for example, a Divination wizard could cast Disintegrate with Portent, to get a similar effect), but it does not fit well with game mechanics. You also can make that list of words up front, so it may spur less creativity than you hope for.

Overall, I think this needs some work, to balance the power between the features better, and to make the features more interesting and less obnoxious in play.

Or, in other words:

The most important thing to know:
Design it well for levels low.
That's where it counts, because today
One rarely sees high level play

How do these features measure up?
Too powerful, -- or power gap?
Let's start with Heightened Imagery
For Truesight free on level three

At sixty feet an epic boon
Third level clearly is too soon
And, really would it be that fun?
Illusions, secret doors, all gone?

It's only 5 feet range, but still
If you're up close, then see you will
And now your bard must run around
To scan each wall and thing that's found

True Rhyme adds to proficiency
and stacks with expertise for three
effects: +10 or better early on
Is nothing here that can't be done

The others won't come up that much
And are the closest flavor touch
With rhymes and bardic pilfering
Of other classes' private thing

For Repetition then on six
Ruling out Force will not stop tricks
Radiant or Thunder are quite close
Hardly resisted by your foes

A cantrip like the eldritch blast
Deals near as much when it is cast
A bard that studies up in Lore
Can pick that up, an then one more

And with a cantrip can reuse it
While Rhyming bards speak once and lose it
This is both narrow and too weak.
And now for our final peek:

Alliteration's ill defined
How many words can come to mind?
It's not that hard to work it out
Well in advance and bring about

That damage henceforth every time
The ones you list don't even rhyme
On top of that: no save, not hit?
Just dealing damage, that is it?

While power-wise maybe OK
This may end up less fun to play
Then what you'd hope for with a class
Maybe give this another pass?