all too often. a particular reflavoring or reskin of a character concept will end up with some problematic abilities that make very little sense for the new concept, this is where i introduce concept based substitutions.
as part of a Reskin of a Class or Race, a character can do the following things for concept purposes
0. a concept must be pitched for the modified character, consisting of a cultural background and home region as appropriate to the setting, as well as values and standards.
1. a character may shift around racial attribute modifiers wholesale to better represent their new species or subrace. the Game Master has final say over any shifted attributes. if an Elf moves their +2 dexterity over to their Constitution, they must place that -2 penalty they would have had to another attribute. maybe they move it over to charisma, this is recommended not only for new Subraces, but for members of existing races that grew up exposed to different cultures or for reskinning a specific race to represent another,
2. a character may swap around resistances or immunities for equivalent resistances or immunities, 1 for 1, conditions for conditions and damage types for damage types. the GM may need to review the damage or condition types being substituted to ensure things are fair. swapping the rarely used necrotic resistance for ubiquitous fire resistance gives a race a lot of defensive gain, swapping cold resistance to gain fire resistance is fine, as is swapping radiant for necrotic
3. a character may swap circumstances for which an ability applies on a one for one basis. stone cunning can instead be applied to woodland areas instead of caves, but should be renamed something like Woodwise. to represent the purpose of the new ability
4. a character may swap out proficiencies and bonuses with weapons or skills for equivalent weapons or skills on a one for one basis. swapping longsword for rapier or scimitar or swapping battle axe for shortsword is fine, or swapping out longsword for katana. as long as the weapons make sense for the cultural background of the species. while trading stealth or insight for perception is fine, trading away animal handling or performance to gain perception is a bit iffy, trading away performance to gain animal handling is fine, this is best reviewed case by case
5. if the character is a member of a class that gains armor proficiencies but not unarmored defense, they can swap out armor and shield profiicencies for unarmored defense as long as they forever opt out of armor proficiency when they multiclass
6. look at the final product, and ensure the character isn't a modified race or class exclusively designed for a single purpose, such as being the best pyromancer or the best scimitar wielder. be wary of cultures developed to thinly veil these solutions behind story shortcuts. you are merely designing a character of an exotic background, not crunching numbers to fight better.