+3 to Charisma is a legitimate choice and also slightly better than adding the +1 to a different stat most of the time. It's also not a typo but intentional, as evidenced by Crawford agreeing that's what the rules say:
Q: Is it intentional that Changelings can put their floating +1 in charisma giving them a +3 to charisma ASI? — ProfNesbitt, Nov 21 ...
There are several published creatures with non-Intelligence-based psionics
By a quick search on D&D Beyond for mentions of "psionics" or "psionic", there are several creatures who associate psionic spellcasting or abilities with ability scores other than Intelligence, including:
Thri-keen (psionics variant), Wisdom-based
In previous editions, many different ability scores were used for psionic PCs.
This answer focuses primarily on PC options from previous editions - an answer looking at NPCs and monsters in 5th Edition would be better suited to the details of the question, but I'm more familiar with player-facing mechanics.
2nd Edition's Complete Psionics Handbook restricted ...
There is an unintended buff to suited, MAD, race/class combos
This modification is intended to promote unusual race/class combos. However, there is an unintended benefit being given to certain race/class combos that are already strong, where the class is MAD. Left unchecked, this benefit could disincentivise certain races from playing certain classes, the ...
The Hexblade warlock's Hex Warrior feature reads (XGtE, p. 55-56):
When you attack with that weapon, you can use your Charisma modifier, instead of Strength or Dexterity, for the attack and damage rolls.
So you may add either your Charisma modifier to attack and damage rolls, or your Strength/Dexterity modifiers as appropriate, but not both.
You may choose to use Charisma instead of Strength or Dexterity
This is covered in the description of the Hexblade’s Hex Warrior feature (XGtE, p. 55-56):
Whenever you finish a long rest, you can touch one weapon that you are proficient with and that lacks the two-handed property. When you attack with that weapon, you can use your Charisma modifier, instead ...
I am not sure this would actually accomplish what you seemingly want, and as for balance I think this is pretty weak.
First I will say that it is important to know what the real problem is here, but if you are wanting to see more gnome barbarians then allowing one point to be moved into a useful stat isn't going to cut it for the type of people who care ...
My groups often had/have a similar house rule to solve the issue:
In games I played in, we often had a similar, but different, rule to tackle the "problem". Basically, we were allowed (and I would allow if I was the DM, though if I recall correctly, noone asked me on those occasions) to get up to 16 score with point buy (spending 2 points for 15-&...
Carefully consider what problem you are trying to solve
In 5e races are not that mechanically different. They have slightly different base stats, and maybe a few bonus special features, that's all. By reducing mechanical differences between races, you are making every choice less interesting. There needs to be meaningful choices for there to be meaningful ...
It seems reasonable from a hard mechanical standpoint.
The way the rule is written prevents people from getting to 18 and from moving the original point-bought which would be problematic since the cost is non-linear and there is another upper limit here (15).
It devalues the half-elf and human
The half-elf and and the variant human can choose any ability ...
Pretty rarely, but there are a few examples
Carrying capacity - The score, not the modifier is used to determine how much a character can carry without becoming encumbered.
Armor proficiency - The score, not the modifier is used to determine if a character can properly wear heavy armors without taking penalties to speed.
Jumping distance - The ...
Modifications work on scores rather than modifiers.
When character gains an ability score improvement, usually at levels 4, 8, 12, 16, and 19 (though the fighter and rogue get more) the characters' ability scores are increased, rather than their modifiers.
The same goes for magic items that increase or modify ability scores, such as the tome of understanding ...
It should be 14 if following PHB rules
As you've noted, Shalvus has a Wisdom of 14, and seems to be proficient in it due to their +4 Perception in their Skill stat block.
However, they specifically call out the Passive Perception as 12, not 14.
There may be another reason, unbeknownst to us, that their Passive Perception is only 12 and not the 14 we'd expect ...