Last time I checked, South Africa was in the middle of a double-dip recession, and already has a fair stock of high-end properties, so a StR may be far away.

Also in recession, but an easier case would be Sao Paulo, Brazil. It's an even bigger financial center than Mexico City, and besides the Park Hyatt (which is poorly located) there are only a handful of independent high-end properties (Emiliano, Fasano, and the Unique although the latter is more of a W competitor). The city only has a subpar SPG property, which is an old Sheraton reflagged from a Melia, in an inconvenient location. Also, no planning restrictions whatsoever, and falling interest rates may mean hotel investments become attractive again.

Buenos Aires shelved its plans for a StR, it would be great to see that revived (the site has been developed into an office block), although the economy is still far from recovery.

Sidney could definitely do with one, as could say, the Algarve in Portugal.

There will be another StR in the Caribbean (besides Puerto Rico), when the StR Riviera Maya opens in 2018.