I am using Hanoi app currently. So my suggestions here are based on that apps.
1. Operating hours for attractions in the See & Do
2. Suggested time to start the tour and time to spend on each attractions in Walking tours
3. It is not clear if the attractions in Walking tours should be visited according to the sequence they are arranged. Perhaps u guys can work on this
3. More hotels (I cant find my hotels in your app)
4. Search function
5. Sending mails for comments, complaints etc from inside the app
That's all for now. Thanks.