That is a loaded question! It depends, even if we would see it as a challenging area, more than a negative one, and as the first step is going to find out the reason for the “negative” space. The unconscious often think in negative and positive and the collective unconscious knowledge for example kept in mind that bathrooms were “bad”. It was probably not an ideal space centuries ago, when there was no proper ventilation, drainage, or cleanliness was not exactly the priority, or accessible to all. It is very different now. Most of the time, bathrooms are well ventilated, drained, and they are aesthetically pleasing.
Missing areas or corners might represent a challenge as well, particularly if they are in the area you would like to see evolve. But they are cures and solutions for almost everything. Feng Shui gives the tools to bring balance to an unbalanced environment, thanks to many elements.
This is more of a geobiological topic, but what could be challenging and would require attention, if people have health issues, is a subterranean water current. That might affect the energy and the overall health, and this needs to be assessed and taken into account.
