The most walkable parts of the most walkable cities have many features that Dongshankou does not. With many blank walls, narrow walkways, lack of weather protection, lack of parks and play areas, and lack of traffic management, there's every reason Dongshan shouldn't attract so many people - and yet it does.
Doorways are a major reason. Paris has zoning codes, heritage laws and financial incentives that discourage chain stores and encourage local and artisanal businesses. Dongshankou doesn't have these measures, with outdated zoning regulations tending in the opposite direction (commercial uses discouraged in residentially zoned areas) but like in the Liuyun Xiaoqu area things are headed in the right direction through force of local insistence and entrepreneurial irrepressibility. Studios, cafes, spas and other businesses are poking holes in those boring walls and attracting more people to pass by and linger.
How widespread is the prevalence of knocking holes in the wall and enlivening the street? The most simple measure is to count the doorways. This particular alleyway, Shuqian Erjie (署前二街) doesn't have many, but the trends are all in the right direction, even if your objective is more to the left.
The traffic management of the area has a Hans Monderman type feel in some locations, with a lack of pedesetrian signals providing effective pedestrian priority through enlightened neglect, but in most areas is distinctly lacking in imagination, with no traffic calming measures and no measures taken to exclude cars despite the huge pedestrian volumes on weekends and holidays and the huge student-related volumes on other days.
Yet despite these shortcomings the area is only growing in popularity. As more doorways emerge, so too will the appeal of Dongshankou continue to improve and expand, and if they actually get around to implementing some improved street design and traffic management, including eliminating the on-street parking saturating the streets and spoiling so many of the photo-seekers' shots, not to mention obstructing people trying to enter the schools, the sky's the limit.