I once created a game world with it's own unique history and races. I tried to balance it between recognizable and novel, so nobody (I hoped) would feel overwhelmed.
I had a player scan over the house rules and he stopped dead when I disallowed Paladins.
"Why are there no Paladins?"
"In this setting, Clerics are the champions of the Gods, and all divine magic comes from Faith. So I felt Paladins were unecessary."
"But you have Druids!"
"Think of Druids more like shamans, they are in tune with spirits of nature and animistic totem spirits. Individually such creatures couldn't grant powers, but in aggregate, they can, provided the Druid uphold the rules of the pact they make with such entities."
"No Paladins is dumb"
"Can you explain why you think so?"
"There's no reason to disallow a class."
"They just don't fit the lore, and I feel their role is redundant."
"You should just change their lore then so they can work. Don't Gods have knightly orders?"
"They might, but why can't a Cleric be a knight?"
"They're priests, they can't be knights."
"Let's see, War Domain. Martial weapons. Check. Heavy armor. Check. Seems Knight to me."
"They don't get extra attack though."
"Most Fighters don't either. You have to understand, higher level characters are rare individuals."
"Level 5 isn't high level."
"To you, no. To most people, yes."
"So I can just kill everyone at level 5? That's a dumb world."
"Not everyone, there are people who can stop you. It's just that not every town guard has a fighting style or can second wind."
"Just let me play a Paladin, and we can say he's a Cleric of whatever made up God you have that's Lawful Good. There, now they fit the lore."
At this point I realized I was just going around in circles with the guy. Annoyed, I said fine, whatever.
"Great. Now why can't I be a Bugbear?"
And this is when I threw my hands up in the air.
I realized then that my players didn't want a unique setting. Or lore. Or history. Or new concepts to explore. They just wanted a game that let them play whatever they thought was cool. It was a sad lesson, but one I took to heart.
For me excluding a class/race/feat, whatever, for thematic reasons is VERY different from nerfing anything. I'll happily exclude something if I think it doesn't fit the theme or feel of the campaign I'm running.
The key is usually trust, if I'm running for my regular group there generally isn't an issue - they know I'm doing it for the fun of the group. If it's a new bunch of players (which hasn't been a thing for a while, too busy) I would be more hesitant - trust must be established first.
Funnily enough, I really like the 5e Paladin implementation, I would much sooner exclude wizards from a world than paladins!