I lived at 6th and Lombard for one glorious year. I loved the neighborhood. In the morning I jogged past Independence Hall, the Liberty Bell, Franklin Court and other historical sites. On the walks to and from work I passed through Washington Square. There's not many commutes where you can walk through a Revolutionary War soldier graveyard and see the Tomb of the Unknown Revolutionary War Soldier, a monument with a George Washington statue, an eternal flame, and a great quote: Freedom is a light for which many men have died in darkness. Washington Square may not have the buzz of Rittenhouse Square, it's crosstown counterpart, but it's quiet solemnity is understated. This is a great neighborhood and a respite from the surrounding excitement - Old City, Society Hill, and South Street.
Beyond the actual Washington Square and the beautiful residential streets the neighborhood lacks a defined attraction to pull people in. Talulu's Garden, off the western side of the square, is one of the best restaurants in the city and has a nice cafe - I usually drink half my Americano in the cafe and the other half in a bench in Washington Square.
The other "attraction" is Jewelers Row, a block of Sansom Street between 7th and 8th, that has jewelers lined up on both sides of the street. Whether it's the Jewelers General gruffy disposition (you are there to potentially purchase a $5,000 ring, you think they'd be a little nicer) or the 8% sales tax (which may contribute to the gruffy disposition), Jewelers Row isn't the destination of once was and now that Toll Brothers has announced they secretly acquired several buildings in Jewelers Row and plan to tear them down and build an apartment complex, forget not being what it once was, it won’t even be.
If you are walking through Philadelphia from Old City to South Street or from South Street back up to Market Street chances are you will walk through the Washington Square neighborhood. In the age of Uber, it may be more convenient to order a driver instead of the mile walk, but you'd be missing out on seeing up close a great neighborhood, not just of Philadelphia, but the U.S.