Funny you should say; I was just exploring around there yesterday.
Broadway between Union and Herald Squares has some gorgeous Second Empire cast iron buildings that look like they were built for small department stores...except the part south of Madison Sq. is upscale, the part north definitely isn't.
But, walking down the whole stretch, I sensed some kind of architectural continuity. I know nothing about the history of the area but it seems like it was probably some extension of Ladies' Mile.
They should try to restore that.
A quick jaunt over to 6th Avenue revealed some new-ish luxury apartment towers and a hell of a lot of vacant lots.
There was a sense of quiet desolation.
I think the whole of Sixth Avenue could use some sprucing up.