virgil wrote:And plucky children/peasants aren't also classic fantasy tropes?
As heroes? Usually not. As secondaries, plot devices, breathing maguffins, and focuses for the main characters yes?
When they are the main character? Then they go on the journey to become the mighty warrior.
Playing such shows a fundamental lack of understanding in how the rules function, and no matter how fun the concept is, the end result is inevitably going to be fraught with frustration and disappointment that will be blamed on everyone but themselves. There are & will be exceptions, but they are the minority, and encouraging such will be detrimental on the whole.
And going from "plucky child as a fantasy trope" to "playing a plucky child" is a false analogy. Generally said child or peasant isn't the protagonist, and when they are they do the training journey of self discovery to become the standard protagonist.
I am opposed to the badwrongfun punishment Lago advocates, and more in favour of just not allowing the option for commoners or true DMFs. Something simple for use so the DM's girlfriend or grandmother can play & enjoy is fine, and I don't care if it allows That Guy (tm) to participate better.
Honestly, I do something similar. When I DM I usually make a fighter the NPC class and have the fighter type be warblades. But if someone is bound and determined to use a fighter, I let them. Cause you know what? Having someone be a basic melee fighter isn't going to make or break the game.
I won't coddle them, nor will I give them special rewards of punishments. But I'm not going to stop them from playing it.