If there was one thing that classic Dark Sun always took flak for was that it was a land of power gamers. We had this inclination ourselves but we countered it by always dealing with maximum hit point monsters and after a certain point working mostly against other character level opponents organized into counter forces. All the advantages we had, they had also so the playing field was leveled.
The power gaming rap is mainly related to the fact that standard ability scores could go up to 20. This was a problem more because the ability bonuses were very nonlinear around between 18-19. Huge jumps would show up at that point so you could get enormous bonus's for most characters if you could get that high stat in the primary ability score. They adjusted this in the revision of Dark Sun but that left the strongest humans on Dark Sun weaker than those on other worlds which did not make much sense. This is not really a problem since 3rd when they essentially linearized all the ability score modifiers but in 4e Dark Sun you generate ability score normally anyway. This is just fine with me, an extra +1 to a modifier does not make or break characters.
Another area which drew in the power gamer reputation was that characters started at 3rd level. Getting through first level was often brutal in normal AD&D. I am not the only person who had entire parties wiped out due to unlucky rolls verses a small band of goblins/kobolds. I think that 4e cut down this problem already with higher starting hit points and these healing surges. Might have even gone to far the other way so maybe the nasty world of Athas can put it back into balance when the characters start at first level again.
One thing along these lines that Dark Sun used to have that does not appear in the new edition that probably should was the character tree concept. Essentially the high mortality rate was countered by having back up pc's that advanced levels each time your active character went up. You could then switch your active character between adventures. The only thing was that you could not trade equipment but since magic items were not supposed to a dominate part of the game so this was not so bad. If it is going to be a brutal setting this might still be needed.
So I think they did a pretty good job of pushing the power levels of Dark Sun characters back in line with other worlds. The people of Dark Sun are no longer faster, smarter, stronger than those on other worlds but the environments is still harsher and life more difficult leading to short miserable lives.