Din Tai Fung is overrated.

I also lived in Shanghai back when you did and recently went back. My friends took me to the Yongkang Road bar area which was great and new for me.

A safe bet would be Din Tai Fung, which is a higher end Taiwanese chain. There are also some local joints, but it might be difficult if you don't speak Chinese.

I lived there for 3 months 16 years ago and am going back for the first time this week. I will only be there 2 days and working most of it, so I'm looking for a quick hit - where can I get good xiao long bo? And if you had a half day to be a tourist, where would you go?