Back in the 70s there was a plan to develop south of Halifax but most of this development never happened. NIMBYism blocked the Northwest Arm bridge, the Armdale Rotary became congested, and some other areas were strategically blocked off as parks.
There was also a plan for a third harbour crossing that would have connected from around the South End container terminal over to the Eastern Passage side. This even popped up again as a tunnel proposal maybe around 2010 or so, but it was never built.
Instead, Bedford ended up with explosive growth.

(Source: Halifax Regional Municipality)