I have always felt it a little jarring when I am in a party that has characters ranging from a talking bird to a centaur with nary a traditional humanoid or human in between.
Not going to comment on "circus troupe", but I agree with you about preferring a humancentric campaign. As an umpire, I have
a strong preference for at least half the PCs to be human or half-human, and the rest to either be common or setting-specific races, with or without the one PC that has to be the monkey in the wrench.
But it's also
setting-specific; since that concept is vanishing from D&D rules and fandom... I don't really know what to do about it. (Besides the
nothing I already do about it most of the time.) But certainly, my views on what constitutes "common" (or even
human) depends on the setting.
Tieflings and Tortles, man. Tieflings are
human in Planescape, common in the Forgotten Realms, and wrenchmonkeys anywhere else. Tortles are
setting-specific in Mystara, and wrenchmonkeys anywhere else.
(Homebrew notwithstanding; when I'm making up an
ad hoc setting, I usually do a couple of rounds of whitelist/blacklist with the players.)
Are there ways I can frame things in my mind to make it easier to get on with?
One thing that helps to
reduce the problem is to insist on doing character creation at the table. The
group creates the
party. They'll make more reasonable choics
and start with PCs they're more excited to play. It's win-win.
Framed that way, it doesn’t seem so strange to me that adventuring parties would be similarly conspicuous within common society.
It's certainly a justified trope from the perspective of verisimilitude... the problem is
genre. It makes the setting less relatable and reduces immersion for the people playing in it.
Weird only gets to be weird if there's a normal to keep it at arm's length. Otherwise, what you have is
surrealism which pretty much detracts from any game unless
it's the point of the game.
I attribute a lot to the 5e rules, where every race is just a human with a different rubber forehead.
It's still bad in 5E, don't get me wrong... but
it used to be worse. I don't think there's a philosophical change at WotC that explains it, but WotC is much more loathe to add new (sub)classes and (sub)races with every supplement.
Even when they do splash out big--
Mordenkainen's-- they're mostly just catching up on legacy content.
Just because axe-grinding is the only joy I have left in life... it's a consequence of how
small the design space of adding a new ancestry has become.
... but I feel that should cut both ways, if there are no aarakroca PCs, there probably shouldn't be aarakroca NPCs either.
Heart of the problem. Most of the "race bloat" comes from monster books; drow, gith, and thri-kreen were all 1E monsters before they became 2E ancestries. New playables are only rarely invented for that purpose.
Monster books don't and shouldn't concern themselves with coherent worldbuilding, but no campaign setting should
actually have all of the species of monsters in the core rules. Goes double for humanoids. And most of the non-humanoid monsters shouldn't even
be species in the first place.
And the players then make up wildly off-brand characters that have little to nothing to do with the starting scenario.
Especially online. Nobody wants to
play your game; they want to
play their character in whatever game they can get into. I can't even run games on some PBP sites because this aspect of playstyle culture is baked into the structure of the site itself.
What do your players want? If they are enjoying playing anything and everything, then lighten up and join the fun!
The GM is also a player; their fun also matters. And this is a problem that makes the game
less fun for lots of people, including a lot of the people that gravitate toward the more exotic character concepts.
Immersion is an important part of "having fun" in a roleplaying game, and a setting with no throughline is hard to get immersed in.
I have a player who has played D&D for almost 30 years and is sick of elves dwarves and humans. He will play the weirdest thing you can offer every time.
I got into the habit because I'm a compulsive mutlticlasser-- in AD&D-- but there's just
not enough meat on the PHB races to make them attractive. (Except humans and their lin.) Likely a consequence of existing simultaneously in so many different worlds and "everyone knowing" what they are.
Weird stuff gets to have an
identity.