Marina Square is closing for a major redevelopment that will add luxury homes, another hotel, serviced apartments and offices to the nearly 40-year-old complex. Hairianto Diman and Elakeyaa Selvaraji examine why refurbishment alone is no longer enough, what makes downtown residential so valuable, and whether this could become a blueprint for reinventing Singapore's ageing malls with Alice Tan, Head of Consultancy, Knight Frank Singapore