At the moment the drains make the bathroom smell horribly and the smell is strong enough to go through the apartment unless the bathroom door is closed and the window open, which is not ideal from a security viewpoint. This must be fixed as soon as possible as it is a health risk.
The noisy neighbours made our nights miserable and would discourage any guest from returning for a visit and as it is impossible to control your neighbours I cannot see a solution. The building has poor sound insulation so you are able to hear every footstep in the flat above, and conversations and even the occupants peeing and flushing their toilet could be clearly heard.
The apartment is well placed for buses and a supermarket but the supermarket closes at 1930 so no late night shopping. Guests need more detail about the bus services to make using them easier. Buses to Venice were often late during our stay, and always crowded, and we nearly always had to stand at least most of the way for up to 25-30 minutes, depending on traffic. There is no other way of travelling there other than taxi so not sure what to suggest. There are some good restaurants nearby but you always need to book, particularly at weekends.