When I recce'd the hotel for our company I saw several variations of rooms, all had windows looking outside. If this is a priority I suggest specially requesting this when you book, and when you check in remind them of this too. We are a company of 60 & no-one complained of wall views so I have a feeling the majority of the rooms have views. FYI: There's a tiny Japanese restaurant downstairs that does really nice, clean food. For those nights you don't want room-service!
Get an answer from Grand Metropark Hotel Nanjing staff and past guests.