I don't necessarily agree it would have gone a "long way". Just my opinion here, but from personal observation, a culture shift from car dependency in Edmonton is going to take a very long time. I lived in the Century, then moved to Ultima when it was complete and watched two more towers (the Foxes) go up. With three new high rise towers up I personally felt or seen no increase in street presence outside of lunch hours and weekend (mostly summer weekends at that). That's in the downtown core even, and people that I knew that moved into these buildings still drove everywhere mostly (although I could say throughout the years they have too slowly started embracing the walk a lot more).
I agree a residential component would have been a better step in the right direction, rather than adding to the demand we deem unfavorable (yes, I am on your side). But there can't be a 'win' on every single inner-city corner and there are plenty of other sites that will have greater impacts. Look two blocks directly South, where is the Brewery District's residential component? Which site would you have rather have residential built first? Would a resi on this site directly impact the potential of Brewery's starting up any time soon?
We also don't know the story behind this redevelopment. Maybe a developer with deeper pockets and higher risk tolerance could have snatched it up. But were any other developers looking at this? How much longer would it have stayed a dead inner-city corner?
This development is going to add to the livability and attraction of the area, where there is still lots of potential for added density. To me, that's a win for now.