I think an enclosed mall makes sense, really. Much like in Toronto (for example), where the downtown buildings are connected by subterranean walkways that are essentially shopping malls, I can see things like this working in areas where the weather is harsh (too hot, too cold, too wet).
It might be that the era of the large enclosed mall in the suburbs is over - who knows. But an enclosed mall in an urban setting like this might flourish.
The renderings look a lot like Westfield Stratford City, the mall complex built before the Olympics in London. That is still doing very well, although it's only been open for about 4 years.