I really like the design both aesthetically and functionally. I think the internal 'street' works well, and I think it looks good from both the west (Dumballs frontage), north (Canal Parade frontage) and east (Park), although I'm less sure about the view of a lot of roof from the south.
Room for expansion seems to be built in (almost doubling the total size) on the proposed car park. At this point, its relationship with Canal Park would become more important.
In the long term I think it will be a good anchor for developments in the Havannah Quay (which I notice seems to have been mistakenly corrected to 'Havana' in new documents), but I do worry that in the short term it might be a bit out of the way.
It would be nice to extend the canal park up to Callaghan Square at some point just to try and (almost) get a green sliver running from the M4 down to the bay. Now all we need is a green high level park (like the highline in New York) to link it to Bute Park! Actually whilst I'm dreaming why not Turf the Stadium's boardwalk??