I'm A Banana
Potassium-Rich
I think that's a bit of a crazy assumption.
I dunno, since 3e began development, balance has always been a very high priority for the devs, so I think that, since WotC knows their audience pretty well, it'd be important for most of their audience, too.
Blatantly making one choice more powerful than the others and then penalizing it by a role-playing restriction is pretty weak sauce.
Similarly, making players unable to access it is pretty weak sauce (makes them unable to do the whole "fall to the dark side" thing).
Making EVERYTHING more powerful isn't bad, but it has some (perhaps mild) ramifications when bringing in outside things.
But I don't really think Dark Sun is about having big numbers. It's about being a tough SOB, honed by generations spent barely surviving on an unforgiving land, but I don't think they necessarily need to do more damage with a fireball or a melee attack to reflect that.