I visited this tentative WHS in April/May 2017. On different days, I walked different stretches of the Seoul City Wall.
Most of the city wall is reconstructed and in a way certain parts reminded me of the Xian City Wall. However, it is worth walking/hiking different parts for panoramic views of Seoul from different angles. The Seoul City Wall museum is a great place to appreciate the wall's importance.
My personal highlights were visiting the 3 remaining main gates and 4 of the minor gates (photo).