Well, to be fair, Ul'dah might be dominated by lalafell but it's population isn't entirely made up of them - all the city states are very much multiracial and multicultural. Also that stairwell does have a ramp on it as well, presumably for this reason. As the stairs didn't exist in 1.0, nor did the Gate of the Sultana it leads to, I'm likely to believe the stairs are a recent addition, but nothing is known for certain.