It sounds like a curb appeal issue. I once sold a house with a very steep exterior staircase and It was the most expensive house in the neighborhood, probably double the average selling price. Lot limitations did not allow me to eliminate the steep staircase. I addressed it by making the staircase very wide, with a turn in it. At the turn, there were plants, a bench, etc. It kind of drew you up and the staircase didn't feel as steep as it was. I also made the staircase out of stone, so it felt substantial.
A friend of mine, who had a very nice house with a steep staircase, took more than two years to sell the house. However, the staircase was made from pressure treated wood and made the (very nice) house looke like a tenament building from outside. My suggestion was to stain the floor boards mahogany and paint the raiing white and try to give it a cottage type look. He never did it. Eventually, it sold. The first thing the buyers did was paint the staircase exactly as I had suggested.
So it brings you back to your very first answer, and several after that. Address the stairs. If you cannot change the grade, if you don't want to spend the money on upgrading the staircase, at least make it as attractive as you can with paint and plants, etc.. If it is steep and narrow, well the price cut you will eventually take is more than the cost of a better staircase.
Re: demographics. It sounds like your buyers would be empty nesters. Young enough to handle the staircase but not a young family who needs 4 bedrooms upstairs for kids. So I woulld advertise it as perfect for empty nesters.
I used some Feng Shui books to help me figure out how to address these types of issues on my house.