I
Immortal Sun
Guest
You'll find that a lot of DMs note that the biggest improvement they made in their games was when they transitioned from making a game FOR the players to making a game WITH the players.
The answer is "yes" and "no". There are some worlds that I make that the answer is straight up "NO. You cannot be that here." because the whole premise of the game simply doesn't work if that thing happens here. IE: a no-magic world where someone wants to play a Wizard. Sorry, no Wizards allowed. No exceptions. Or a single-race or limited-race world. No exceptions. I've played with people who always need to be the odd-man out, and I've made allowances for that using the "under the hood" technique, where you play as whatever race you want mechanically but you are visually a member of one of the available races.
But a setting needs some level of integrity and working with players is not an excuse to let them run roughshod over the setting premise in order to aid their need to special. Some settings just require a higher level of integrity than others.
However, I will also tell players to hear out the whole premise before simply "making a character". IE: we're doing a drow campaign, where we play drow, and participate in drow politics, so after explaining that, if someone shows up the next week with a lizard-man character (literally, this happened, right after I explained the name of the game and they agreed to it!) I will hold up a firm hand and say NO.
I know a lot of folks here promote the idea of "Yes but..." BUT quite frankly sometimes you gotta say "NO". I worked in retail. I know what happens when you say "Yes" or even "Yes but..." to customers. I've no desire to replicate that kind of arrogant entitlement at my table.
I have a kitchen sink setting (two actually!) for people who want to play Wizards & Weirdos. I have two racially-limited settings (A human-centric world and a drow setting) for people who are willing to play something more specific. I'm happy to run my kitchen sink game for folks who want to play that way. But I'm not going to compromise the integrity of my other settings because they want to be special.