To me the area's in red below are the biggest gap/holes in our downtown that keep it from being a cohesive unit. If we work to fill these holes - which the Donald/St Mary and hopefully 285 Smith projects will start, I feel that downtown will just have manageable holes (single empty lot as opposed to a wasteland like in red).
I am not including the Main St strip (around York) and the Forks as they are on the edge of downtown and don't give the same feeling like the gaps in it's center.