I don't understand the desire to take up precious land by adding new roads (Bates extension), especially to an already road-dense part of downtown Birmingham.
True, the existing surface lot is ugly and inefficient.
But why not instead of extending Bates as a road, make the extension a walkable veranda lined with retail/office space, including a walkable/bikeable bridge over the Rouge River and connecting to Booth park?
It would form a much more friendly connection between the north shops and downtown vs. the way too tiny and car-infested sidewalks along Old Woodward.
For a fun twist and convenience, connect the west frontage to the east frontage buildings on either side of the veranda with a second story pedestrian bridge running through the east building for access to the new parking structure.
The veranda could have trees through the center and benches and tables.