Ever since the old Connaught Bridge (which connected to Robson) was replaced by the current Cambie Bridge (connecting to Smithe and Nelson),
Robson has declined in status as a transportation corridor.
Its role as a shopping street has risen, while its role as a transportation corridor has waned.
If they opened up Haro to traffic - and removed this restriction (pic below), Smithe / Haro would connect into the West End.
Alternatively, Thurlow could be made 2-way north of Nelson (or for its entire length) to access other east-west streets.
With the changes at the north end of the Burrard Bridge, you probably don't want a massive flow down Thurlow to Burrard Bridge anymore,
since the right turn (eastbound Pacific to bridge) will be a traffic light controlled movement.
http://www.bing.com/mapspreview?q=robson+and+haro+vancouver&mkt=en&FORM=HDRSC4