What’s the setting? What’s the campaign about?
Can you answer these questions in one sentence as a pitch to a prospective player?
I don’t know if many game masters consider questions anymore.
Most, at least in my area, seem to only run what’s commercially available. They go with the default, whether it’s the Forgotten Realms or Golarion. It’s somebody else’s creation. They’re telling somebody else’s story.
Published settings come with lots of options for players. And game masters don’t have to do the heavy lifting of creating their own. That’s the appeal.
Players can run whatever character they’d like. If you want to play a dragon-born fighter/wizard, you can head for the Forgotten Realms. There’s room there.
But not in my homebrew campaign setting.
I don’t even allow elves. They don’t exist. Neither do halflings.
They just don’t mesh well with my campaign setting and concept:
The Northlands are on the fringe of civilization where human characters explore the wilderness in search of treasures, lost ruins, and other mysteries in a sandbox campaign.
Maybe that’s not the best hook, but prospective players have an idea of what to expect. Those who really want to play a gnome or an ogre character will probably pass, but that’s okay.
A good concept is supposed to dissuade players who might not enjoy your game. It takes care of problems before they become problems. It sets expectations.
This way, you have player showing up running ogres if you’ve intended for an all-dwarf campaign, and the like.
I used to think more options can make better game. Now I believe fewer options can deliver a better experience for GMs and players.