The texture of their skin is hardly what makes dragonborn incredible. And 3ft tall people wouldn't be at nearly as much a day to day disadvantage as you think. Halflings would have less of a hard time than real life Little People, in day to day activities. They aren't toddlers, they're adults with adult skeletal and muscular structures, reflexes, and awareness of their surroundings and their body.
Your commentary about dodging has nothing to do with halflings, its just a blanket argument against dodging attacks. Not a compelling one, either. It's an action game. Characters dodge. Big shrug. A 9 year old can dodge a lot better than an adult, IME, because of their size and how easy it is for them to move that weight quickly in a short burst. Play nerf tag with some kids.
Now, if they remained about that hieght and wieght into adulthood, with better natural reflexes than a human, halflings are close enough for a game that doesn't get more nitty gritty than "dex means agile regardless of strength score".
Now, if you thinhk that the Hobbits were non-combatants who just needed protecting...are you sure you read the books? Because you're objectively wrong about that.