You suggest that Coburg road  "should have another lane" and then seem to lament that "soon we’ll be tearing into some of these buildings to take room for more road." Are you suggesting that we should build another lane but that we should not build another lane because we would would tear down buildings? That seems a contradiction.
As far as adding another lane, that would be two lanes, one each way, for a total of 7 with a center turn lane. At a minimum of 11 ft each, with two bike lanes of 5 ft each, is 87 feet. Now we're talking pedestrian challenge of crossing that much highway were I saw a woman killed trying to cross.  To do this the City would have to acquire the land from the land owners, giving up parking. And, as you note, businesses now abutting the sidewalks would have to be relocated. Like the car wash, burger joints, Mexican restaurants, and some homes. 
But if as you suggest that we slow development by not allowing these buildings, then people scream we are anti growth.