I agree entirely. I feel like a Rec Room or something similar would be a great addition, for example. A better and more accessible movie theatre would also be great, maybe not as much for those from the suburbs, but for people who are Downtown or in the closer neighbourhoods like Winketowin, Garneau, Old Strathcona, QMP, etc., who currently have to drive far to go to a decent one, and have to deal with ECC (closest one if you're north of the river is on 137 Ave/Mark Messier Tr or WEM, and if you're south of the river it's SEC).
Another commonly mentioned thing is a good hardware store, and I wouldn't be mad at something like a Simmons or even a Mark's downtown (their Westmount location is not particularly great or large, and I feel like that whole area will eventually be redeveloped anyways).
I feel like keeping people from central neighbourhoods in the area, and bringing them to DT is as, if not more, important than attracting people from the suburbs.