I would not describe the negative reaction to 4e Dark Sun as "big" in any context besides "big among a few hardcore fans on some small forums."
Edit: Let me add that, as snarky as this comes across, I don't want to belittle those hardcore fans. 4e Dark Sun does make some big fundamental changes...
You have the right to take issue with these treatments of elements of your heritage if you feel they are problematic. But the fact that you don't see an issue, or that you do and choose not to take action about it, does not mean others can't do so in their own circumstances.
I don't expect a new writeup for kobolds explicitly, just whatever new rules for changing racial mods to cover it. As for Purebloods, they gave Satyrs magic resistance, so I suspect they aren't too concerned.
It doesn't really come across in the books themselves, but in interviews and such the developers have mentioned that some spells, items, and even subclasses (to a much smaller extent) are made in mind more for monsters and NPCs than for players.
Honestly, the biggest reason is that ability score penalties are not popular. They've been falling out of favor in D&D for years, and as soon as Volo's came out everyone knew if they did a setting like Eberron that orcs would get revised stats.