In the immortal words of professor Xavier every gnome weeps for the unfortunate soul of the slavers who think they can take one of them with impunity. Nibenay, an epic tier sorcerer/psionicist tried to destroy them and failed because he, like every one underestimated them. They were seen weak because they were wellcoming and jolly. The hidden truth no one save Nibenay knows is that the first time he tried to cleanse them they fooled him thoroughtly. Then King of the Gnomes was an epic psionicist named Garlaad the Laughting, who humiliated Nibenay with his tricks and buyed time for his people to hide in the Wind, when the enraged champion returned to try again. Many gnomes died in that day but way less of what is believed. Gnomes believe that laughts and joy keeps you alive as much as food and water does, and that who is rich on friends is poor in troubles. On the other side who tries to take advantage of the Laughting People will soon found out that the joke is on them.
Good natured and happy Gnomes fly in the face of the brutality and general feel of Dark Sun. If a peraon wants to include them that way, that’s fine, but i seriously doubt they’ll find acceptance from other DS fans for that idea - its basically against a central trope of the setting.
I’m not saying don’t do it, but I am suggesting you are probably going to need to accept that nearly no one will understand why you’re doing it. You’ll like have to put younfoot down, say “I’m doing it, hard stop” and then be very specific about what further input you want.
Otherwise, i suspect all they’ll be doing is constantly explaining and justifying their plans, and nobody deserves that.
It would not be the first time, I put deities, in a fashion, in my Athas, putting happy gnomes would be a minor cosmetic change, in comparison.
Gross. Good for you! 
It flies in the face of a current Athas. As yes - I realize that the previous team and current team has ruled that Athas has always been savage, but the trope of a previous golden age of peace, prosperity and happiness is also a common one that you could easily apply to Athas without damaging the setting, so long as this situation is no longer extant in the current age.
Extant, like, say…a bunch of happy go-lucky living gnomes? 
Yes. Surviving into the current age, they would have to be resentful, suspicious and angry folk.
I’m warming to the idea of laughing gnomes. But not laughing because they are happy, more because they are psychotic.
If you want to add happy Gnomes, add happy Gnomes. Gods though? Inconceivable!
Well, I did it so…not so inconceivable now, is it? My Athasian gnomes are living testaments of one simple truth: Morality is a choise, and you can be a kind person in an unkind world. It is not easy, there are not millions if them thriving in the world they are way less then Halflings or Humans, to say the least. But they go on, staying faithfull to themselves and smiling to the world’s scowl. As a Gnome Saying goes “Athas is brutal and harsh but it was not always that way, and there is no need to let your heart turn sand too”
Gnomes on Athas? son of a… someone call Gallard quick! oh none existant gods, they’re breeding!!! 
I think we’ve all been trolled
If you meant by me, no.
Don’t you mean gnomed?
Personally, I think having a group of people who chose happiness in the face of Athas is an interesting idea, and not necessarily out of scope for the setting.
If Athasians can be stubbornly savage, stubbornly selfish, and stubbornly destructive… then why not have a group who clings to stubbornly happy?
Could be a coping mechanism, could be delusion, could be psychosis, could be a philosophy, could be a remnant religion, or something else.
In a post apocalyptic world of weirdness, it is a possibility not beyond the pale.
Thanks you said it better then me.
Great, why not add Puppyfolk to the setting next and maybe a dwarven grandma knitting alliance that’s planning on taking down the SK’s one at a time using psionically empowered handknit loin cloths for an army of very polite and dutiful Rikus clones.
Frankly I feel like the people of Athas would have cleansed these Gnomes even after Gallard hung his hat up and popped a squat in Nibenay, just out of shear spite and frustration.
No one is forcing you to add them to your Athas, you know?
Like what happened to the Kender?
Kender steal things, Gnomes make people laught, a bit different I’d say. If there is a place in the multiverse who nees a bit of joy is Athas.
Maybe Kender stole things from gnomes. For example, gnome lives. This is Dark Sun, after all.