I don't think Dragonborn are stupid. I accept them as a fantasy element.
What I find unbearably stupid/annoying is the way all the races are forced together into the same culture. The serving boy at the inn could a dragonborn or an elf or a tiefling or a human. There's no difference. The races have become costumes, nothing more. It completely destroys the setting, imo.
I'd rather see the races presented as having their own societies and cultures. Where an elf is long lived and thus almost mystical and frightening to a human. Where caste systems are in place, where tensions run high, where alliances mean something.
As it stands, it currently feels like a random race generator was used to pick whatever race the NPC happens to be, regardless of the role or place in society.
I mean it's kind of hard to give Tieflings a culture since they're hybrids with three quarters of human DNA,
also Pretty Sure the Elves already have a bunch of cultures, there's so many Subraces:
. Elandrin live in the Feywilds which is a separate plane where fey creatures come from, They're like Purest version of Elves,
. High Elves can be Split into the Entitled, Magical and Racist Sun Elves/Gold Elves, Friendly, Nomadic and Tolerant Moon Elves/Silver Elves and Isolated Star Elves/Mithral Elves, High Elves are also like a watered down versions of Elandrin, The Elandrin that moved to the Material Plane became the High Elves
. Wood Elves/Copper Elves are Nature loving Tree Huggers often gets confused with Wild Elves
. Wild Elves/Green Elves are are like Wood Elves but less civilized and more Feral
. Drow/Dark Elves that likes BDSM, Spiders, Slavery and Misandry
. Aquatic Elves, Blue Skinned Water Breathing Elves that live underwater, they resemble Tritons but with pointy ears
. Avariel aka Winged Elves
. Lythari the Rare and Reclusive race of Werewolf Elves
. Shadar Kai Super Edgy Elves (They're bigger Edgelords than the Drow which is saying something) that live in the Shadowfell and serve the Raven Queen
