>does this make her more righteous?

The only one left with a righteous ambition or even "legal" claim for the throne aside from Dany is.... uh... well.... the Baratheon bastard. She actually wants to rule in a way that benefits her subjects. Can anyone else say that?

Stannis is far from righteous, as evidenced by his desire to murder innocents on his way to the throne. There's been nothing to indicate he has a desire to rule in a way that benefits anyone but himself and his methods are questionable at very best because of it. Sure, he's been taken in by Melisendre's charms, but he's had wise and reasonable counsel and ignored it. His tactics have no pure motive behind them.

Joffrey is a vile, evil king without a legit claim despite not knowing it.

Tywin is a megalomaniac and wants power more than anything. His actions against the Starks are justifiable in that they are at war with one another, but his BEST motive for anything is self preservation. And then there's the question: what has he done for anyone else that wasn't mere political back scratching?

Dany is the only one angling for the throne for reasons and in ways that aren't entirely self serving. What genuine good has anyone else done for anyone? Margery is the only other player in this game to show a hint of concern for the people she may one day rule, even if it was little more than a blatantm obvious and mundane political gesture.

No, Dany has shown genuine care and concern for her people during her ascension. Despite needing an army to do her conquering, she gave them a choice at a time when she had zero means of reneging on her promise to free them. What could she have done? She gave them the choice to serve under her. Perhaps they were progammed to be warriors and did so out of their own code, knowning no other way and perhaps she knew that. Her treatment of them has still been stellar. The slaves she just freed, on the other hand, aren't soldiers. Mind you, she did this after turning down a considerable financial offer to leave that would have served her quest for the throne exceedingly well.

She is infinitely more righteous in her quest than anyone else currently pursuing the crown.