OK - so this has been gnawing at me for a while so I just stayed up and did some playing around with photoshop again.
Let me preface by saying that while what they are doing in Markham and Vaughan will probably be OK, I don't like that entire sections of the development will have a cookie cutter 'developer' look to it, which is even worse when they're trying to emulate old world European streets and alleys, etc...
My preference would be to build up an MCC 'downtown' (or whatever) using layouts that we'd see in North America. Square/rectangular blocks (with the occasional deviation) with smaller, individual looking building facades that might range in width from 16 to 50 feet. I would do these, however, around parking structures that would be 3 or 4 levels in height. Eliminating surface parking is a key element and with the additional visitors/residents it will be important to accommodate visitors to Square One (whose parking is being consumed by this) and the new 'downtown' that don't come by transit.
The parking structures are built to accommodate first floor retail with high ceilings. Retail condo units would be sold which includes the facade all the way up to the top of the building. The overall height of the buildings would be in the 4~5 storey range and facades would extend to at least this height. Allowing varying heights will look less cookie-cutter. It's up to the owner of that particular "building" to design and build up to the required height and it could be brick, stucco, glass, whatever - as long as it meets some minimum criteria (height, emulation of additional floors).
The zone is comprised of 6 main blocks and 3+ surrounding blocks, all geared with ground floor shopping, restaurants and services. Running down the middle would be a pedestrian only street/promenade. Think Sparks St in Ottawa. This is where key retailers will want to be and should have a heavy concentration of eating establishments. It might be possible to work in a 2nd floor of office or retail in some parking structures, or maybe just those facing the main pedestrian promenade, but this is secondary.
By creating 7 such parking structures on existing Square One parking land, the number of spots on these lots would double or more - triple being the ideal - in order to handle seasonal highs and/or events in the core.
I've attached the following (rudimentary) plan for the area, laid out to scale over satellite photos. There are proposals for streets where none exist, and others be extended to create a more complete set of blocks to get around within the zone. I've shaded in what would ideally be a good size hotel (with ground floor retail + restaurants)... say on the level of a Sheraton, Marriott, Hilton, etc... as well as a future high rise office tower located across from the Bay parking garage, opposite Ruth's Chris on Kariya Gate. The lot is screaming for an office tower IMO.
So without further ado, here is the first revision of the plan:
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Goal is to have a feel like this...
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...and for shits and giggles, here's an aerial render of what
could happen down the road with additional high rise office towers (say 30 ~ 45 stories) being added in along Hurontario, as well as the office tower+hotel I've shaded into the plan. I tried to put in placeholders for Absolute World, Wide Suites and what will most likely be more condo towers along Burnhamthorpe between Kariya and Living Arts Dr.