This is all up to the player to make a character who works by the rules of the game.
If you can't make a character raised in nobility who became a Barbarian work, then don't make that character.
It's as simple as that.
If a player responded to our table the way you're doing now they wouldn't be welcome to play.
Play in good faith.
And yet you have not told me which rules I am breaking.
Variant Human, Ancestral Guardian Barbarian, Noble (Knight).
What rule am I breaking? How am I playing this character wrong? You know nothing else about them accept that they wear armor (barbarians get medium armor proficiency), use a shield and a longsword (barbarians get shield proficiency and martial weapon proficiency), they are well read, literate, polite in polite company (we rolled for stats at the DMs insistence, I had a 12 Intelligence, 12 Charisma, and 14 Wisdom on top of my impressive physical scores. He wanted a high powered game and so the DM was happy. And we rolled digitally, so there was no cheating before you decide to accuse me of that).
He was a questing knight, looking to commit deeds of heroism and strength to honor the Princess who was his Lady, following the ideals of Courtly Love.
When battle started he would enter a battle frenzy, calling to the spirits of his ancestors to guide his sword, and I used all of the barbarian abilities granted to me by my class. I generally charged into the thickest section or the enemy spellcaster, knocked them down with my shield master feat and attacked them with my sword.
What rule did I break? Why would I be unwelcome at your table, because I refused to play an illiterate brute? Because I refused to be rude, quaff ale and belch? Because I wore nice clothes?
Most tables are going to expect the player to make a character who is an adventurer. Making a character who just wants to attend to matters of state or run their artisan business, or live alone in the woods, etc. would not be acceptable at most tables.
The game is designed around characters forming a party to go on adventures. Make a character that works for that.
I did.
You still say I broke the rules. That my character wouldn't be accepted by the table. Why? What did I do wrong?
This is something that gets said over and over again. The implication here is that it is more imaginative to play a weird character or one with a gimmick or what have you than one of a strong classic archetype.
Make a memorable Wood Elf Ranger. That takes imagination and skill.
Improv actors show their creativity by working within the rules given to them. It's not creative for them to just come up with random things and change the rules because they can't think of anything within them.
Putting Noble and Barbarian together is not a flex of someone's imagination. That doesn't take much creativity. Picking Barbarian because they want the Rage mechanic isn't a player being creative.
Playing a Kenku or a Thri-Kreen or an anthropomorphic rhinoceros is not more imaginative than playing an Elf or a Human even if they aren't seen as often.
I've seen it all before. It's not clever.
Make a memorable character not just a gimmick.
I like how people can say one thing right, and be so wrong on the rest.
You are right, working within limits can lead to interesting stories. Just breaking the rules for the sake of breaking the rules is not interesting.
Of course, playing a noble with the barbarian class is not a gimmick either. Beowulf, Prince of the Geats who fought a monster barehanded and ripped its arm off, who constantly shattered his own weapons, would probably be a barbarian. I doubt we can call it a "gimmick" to copy a two thousand year old famous text. Seems really like a strong classic archetype. Kind of like a wood elf ranger, that has been a thing for 60 years?
And that is the crux here. You have stood upon the mountain and made a value judgement on other people's stories. Without actually caring if they are making an interesting character.
Are Shifters interesting? How about a young girl banished and excommunicated from her tribe for learning the dark secret of a shaman, forced into a world she doesn't understand, falling into vice as an escape from the depression of losing her people?
Paladin Criminal is a "gimmick"? You think a character who was a smuggler, getting caught up in a demonic betrayal of a cult, and was granted power through his overwhelming desire for Vengeance against that cult is going to have no desire to adventure? No interesting stories?
Unless you have a superpower to judge a character from across time and space from only their name, how can you stand there so smug in your superiority and declare what the rest of us are doing as drivel?
