I look at The Bounce basketball courts in Calgary's East Village and I see how successful that space - as "small" as it really is - brings community together. No doubt that basketball court and the event space it provides has really added to the walkability and enjoyment of the area. I hope Edmonton can emulate the same concept, and it seems so simple - installing a basketball court, or workout equipment, or physically engaging streetscape and activities moves the needle to get people in and around the area.
Lack of green space in the downtown core was something that was seared into my head when I moved to Edmonton and the one mental block I had - it was a concrete jungle - literally, with all those parking lots. The removal of that changes the game for me, especially since the Warehouse District in downtown has so much potential to do things "right". A central park area (and with courts and those kind of amenities) completely changes my view on spending time in that location.
Personally I would love to have a futsal court in the area as well - we have an international population base in Edmonton that absolutely adores soccer, and we have Edmonton FC with the CPL that is growing in interest to boot. Why not cater to the soccer crowd in a central location too? I have no doubt it would be mega popular in the warm months.